coltrinit – Page 18 – jasoncoltrin.com

Exchange 2010 Installation Part 5

Absolute Necessities for Exchange 2010

You need an Active Directory Domain in place
You need a solid DNS infrastructure
You can technically install Exchange 2010 on a server that is your Active Directory Server and your DNS server (case in point, Small Business Server)

Typical or Custom Installations:

Exchange 2010 can be deployed through either a Typical or a Custom Installation

1. Typical: will install the Hub Transport, Client Access and Mailbox Server roles

2. Custom: You can install one server type, or some, or all of the roles

If you install the Edge Transport (greys out other roles), you cannot install other roles. Can only exist on a DMZ
If you are installing one of the other roles, you can combine them together (you may install them on separate servers all together.)
You don’t need the Unified Messaging Server role in order for your organization to function. The same with the Edge Transport server, not required but is recommended by Microsoft to provide better protection for Exchange.

The installation itself is fairly typical, and if your prerequisites have been installed you should not encounter any errors.

After installation, if your Exchange server is not licensed, you will have approximately 120 days to activate or license the server.

Be sure to check for critical updates for your exchange server after installation. If you don’t see any updates for exchange in Windows Update, even after a reboot, you may need to start the Exchange Setup.exe Installer again, and click on “Step 5: Get critical updates for Microsoft Exchange”. This is the only way I could force Windows/Exchange to find new updates, for example Exchange Update Rollup 5 for Exchange Server 2010 KB2407113.

Exchange Updates — Click Image to Enlarge

Everything we need installed for a working Exchange environment has been accomplished.

When starting the Exchange 2010 Management Console, we are not simply opening it for this server, but for our Exchange Organziation. Whether on a single server, or a multitude of servers, the console will manage the entire Exchange Organization system.

For the Edge Transport Server

We will install Active Directory Lightweight Directory Services. Even though the Edge Transport Server is not a part of the AD (for our own safety) it still requires a directory to work with. We can install it via the GUI, or through the PowerShell.

For the Edge Transport server, we will use the code:

> import-module servermanager

> Add-WindowsFeature NET-Framework, RSAT-ADDS, ADLDS -Restart

When running the command you may receive the following result error:

PS C:UsersAdministrator> Add-WindowsFeature NET-Framwork,RSAT-ADDS,ADLDS -Restart
Add-WindowsFeature : ArgumentNotValid: Invalid role, role service, or feature: 'NET-Framwork'. The name was not found.
At line:1 char:19
+ Add-WindowsFeature <<<<  NET-Framwork,RSAT-ADDS,ADLDS -Restart
    + CategoryInfo          : InvalidData: (:) [Add-WindowsFeature], Exception
    + FullyQualifiedErrorId : NameDoesNotExist,Microsoft.Windows.ServerManager.Commands.AddWindowsFeatureCommand

Success Restart Needed Exit Code Feature Result
------- -------------- --------- --------------
False   No             Invali... {}

If you receive this error, it means that the prerequisite, .NET Framework 3.5.1 is required. See screenshot below. An easy way to install the prerequisite is to use the GUI role installation feature, which will prompt you to install the framework. Be sure to apply all critical updates and service packs to .NET prior completing the installation of Lightweight Directory Services; remember, this is your public-facing computer.

.NET 3.5.1 required — Click image to enlarge

Once .NET and the rest of the Edge Transport role is installed, you’ve rebooted, updated and have rebooted again, now would be a good time to backup the Edge Transport server with either a bare metal/VM system snapshot. Although snapshots are beneficial, an Edge Transport XML export/backup should be performed as well on a regular basis. I exported my first as Edge_BaselineXML.

A very useful article on backing up and restoring the Edge Transport Server can be found here: http://exchangeserverpro.com/exchange-2010-edge-transport-server-backup-and-recovery

Note: The Windows Backup feature is not installed by default on a newly installed Server2008 R2 installation. You can quickly install the backup feature at the powershell using the following two commands:

> import-module servermanager

> add-WindowsFeature backup

When logging into the Edge Server, and launching the Management Console, I encountered the following error:

[ERROR] Provisioning layer initialization failed: ‘Active Directory error 0x8007052E occurred while searching for domain controllers in domain

The problem was that I had logged into the local machine only and not the domain, and when trying to run the console, it was not logged in as a domain user. I logged off, logged back in as DOMAINAdministrator, and then found the Management Console to work correctly and identify my machine as an Edge Transport Server.

Another error I hit was the following:

The following error occurred when searching for On-Premises Exchange Server:

The term ‘C:Program FilesMicrosoftExchange Server V14BinConnectFunctions.ps1′ is not recongnized as the name of a cmdlet, function, script files, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. It was running the command’. ‘C:Program FilesMicrosoftExchange ServerV14BinConnectFunctions.ps1’

(Click here to retry)

By following the workaround here: http://blogs.technet.com/b/nawar/archive/2010/09/03/exchange-management-shell-ems-missing-after-applying-exchange-2010-sp1.aspx I was able to continue with the configuration and open up the Exchange Console. However, all roles were available, which is incorrect. We should only see the Edge Transport role. After re-installing only the Edge Transport Role through the Exchange Setup, I now have the Edge Transport Role up and running. The Exchange Management Console should show only the Edge Transport Role on the Edge Transport server itself.

This makes it clear what we’re working on. We’re on an Edge Transport server and that is all we can work on.

At this point we now have the ability to send mail internally from one mailbox to another. We do not have the ability to send email to the internet or from the internet because we have not configured DNS, or our Send/Receive connectors. We will save these tasks for a different post.

A good majority of the content provided in my Blog’s Exchange series is derived from J. Peter Bruzzese’ excellent Train Signals Exchange Server 2010 Video Disk Series, as well as my own Exchange 2010 lab. Trainsignal.com is an invaluable source for accurate, easy to understand, IT information and training. http://www.trainsignal.com

Exchange 2010 Installation Part 5

Absolute Necessities for Exchange 2010

You need an Active Directory Domain in place
You need a solid DNS infrastructure
You can technically install Exchange 2010 on a server that is your Active Directory Server and your DNS server (case in point, Small Business Server)

Typical or Custom Installations:

Exchange 2010 can be deployed through either a Typical or a Custom Installation

1. Typical: will install the Hub Transport, Client Access and Mailbox Server roles

2. Custom: You can install one server type, or some, or all of the roles

If you install the Edge Transport (greys out other roles), you cannot install other roles. Can only exist on a DMZ
If you are installing one of the other roles, you can combine them together (you may install them on separate servers all together.)
You don’t need the Unified Messaging Server role in order for your organization to function. The same with the Edge Transport server, not required but is recommended by Microsoft to provide better protection for Exchange.

The installation itself is fairly typical, and if your prerequisites have been installed you should not encounter any errors.

After installation, if your Exchange server is not licensed, you will have approximately 120 days to activate or license the server.

Everything we need installed for a working Exchange environment has been accomplished.

For the Edge Transport Server

For the Edge Transport server, we will use the code:

> import-module servermanager

> Add-WindowsFeature NET-Framework, RSAT-ADDS, ADLDS -Restart

When running the command you may receive the following result error:

PS C:UsersAdministrator> Add-WindowsFeature NET-Framwork,RSAT-ADDS,ADLDS -Restart
Add-WindowsFeature : ArgumentNotValid: Invalid role, role service, or feature: 'NET-Framwork'. The name was not found.
At line:1 char:19
+ Add-WindowsFeature <<<<  NET-Framwork,RSAT-ADDS,ADLDS -Restart
    + CategoryInfo          : InvalidData: (:) [Add-WindowsFeature], Exception
    + FullyQualifiedErrorId : NameDoesNotExist,Microsoft.Windows.ServerManager.Commands.AddWindowsFeatureCommand

Success Restart Needed Exit Code Feature Result
------- -------------- --------- --------------
False   No             Invali... {}

A very useful article on backing up and restoring the Edge Transport Server can be found here: http://exchangeserverpro.com/exchange-2010-edge-transport-server-backup-and-recovery

> import-module servermanager

> add-WindowsFeature backup

When logging into the Edge Server, and launching the Management Console, I encountered the following error:

[ERROR] Provisioning layer initialization failed: ‘Active Directory error 0x8007052E occurred while searching for domain controllers in domain

Another error I hit was the following:

The following error occurred when searching for On-Premises Exchange Server:

(Click here to retry)

This makes it clear what we’re working on. We’re on an Edge Transport server and that is all we can work on.

Exchange 2010 Installation Part 4

Updating Your AD Schema and Preparing the Domain.

What is the AD Schema?

* Consider it like the blueprint for all your objects and attributes within AD.

Do you need to update the schema?

* Not in smaller environments (unless it is a policy) because it will occur automatically if you install Exchange with an account that has permissions to prepare AD and the domain.

We prepare ahead of time from the command line the commands are:

-Setup /PrepareLegacyExchangePermissions (or setup /pl)

-Setup /PrepareSchema (or setup /ps) ( this will also do legacyexchangepermissions)

-Setup /PrepareAD (or setup /p) ( this will also do schema and legacy)

Make sure you’re in enterprise admin group and for schema, schema admin group.

How do you prepare the domain?

* From the command line the commands are:

– setup /PrepareDomain (or setup /pd)

– Setup /PrepareDomain:<DomainFQDN>(or setup /pd:<FQDN)

– Setup /PrepareAllDomains (or setup /pad)

You can confirm that these commands completed successfully by looking for the organizational unit called Microsoft exchange security groups (10-11 security groups created).

Give this time to replicate throughout the organization.

I ran:

D:> setup /PrepareAD /OrganizationName: jasoncoltrin

You can cancel the setup.

You can co-exist with an existing 2007 environment. So you can be running Exchange 2007 and 2010 at the same time. However, you cannot install/run Exchange 2007 after 2010 is installed first.

Once this finishes, you will run

D: setup /PrepareDomain

That’s it, your environment is now ready to install the Exchange 2010 system in your domain.

Exchange 2010 and Server 2008 R2 Prerequisites Installation Part 3

Server 2008 R2 Prerequisites Installation:

This sub-section will guide you to prepare your Active Directory and Domain environment.

1. To perform this tasks we need an User ID with Schema Admins, Domain Admins and Enterprise Admins group membership.

2. In the Active Directory Domain Server run the following command

Go to Start | Run | ServerManagerCmd -i RSAT-ADDS .This command will install the Active Directory management tools.

3. In the Active Directory Domain Server run the following command.

setup /PrepareAD /OrganizationName: or setup /p /on:

Note: In this command is a variable this will vary according to your environment Ex: setup /PrepareAD /OrganizationName:jasoncoltrin. Before run this command browse to Exchange 2010 binaries path or include the Exchange binaries path Ex: “M:Setup.com /PrepareAD /OrganizationName:jasoncoltrin”

For Hub Transport and Mailbox servers install the MS Filter Pack. The filterpack can be found here: http://www.microsoft.com/downloads/en/details.aspx?familyid=60c92a37-719c-4077-b5c6-cac34f4227cc&displaylang=en . Be sure to install the 64bit version. Run the setup wizard, and complete the install. *Note: On Exchange 2010 RTM, you can meet the prerequisite by installing 2007 Office System Converter: Microsoft Filter Pack. However, MS recommends that you upgrade to the Microsoft Office 2010 Filter Packs.
In the PowerShell, type Import-Module ServerManager – Open powershell. type in import-module servermanager.
Use the Add-WindowsFeature cmdlet to type (in actuality it’s much easier to install the features throught the PowerShell). Go to TechNet page here: http://technet.microsoft.com/en-us/library/bb691354.aspx and find the bullet that lists: “Install the Windows Server 2008 R2 operating system prerequisites”. Below is the command:
Add-WindowsFeature NET-Framework,RSAT-ADDS,Web-Server,Web-Basic-Auth,Web-Windows-Auth,Web-Metabase,Web-Net-Ext,Web-Lgcy-Mgmt-Console,WAS-Process-Model,RSAT-Web-Server,Web-ISAPI-Ext,Web-Digest-Auth,Web-Dyn-Compression,NET-HTTP-Activation,RPC-Over-HTTP-Proxy,Desktop-Experience -Restart

Click to enlarge image

* As an alternative you can run the script from the Scripts folder on the Exchange DVD. Go to Start | Run | cmd | Browse to Exchange 2010 Binaries Scripts folder by using cd Scripts command | Run ServerManagerCmd -ip Exchange-Typical.xml –RestartNote: This command should be run from Scripts directory of Exchange 2010 DVD *Note: it’s a good idea to extract the Exchange 2010 binaries to a folder off of your C: drive (something like c:exch2k10, so that it’s easier to find the “Scripts” folder.)
Note: If you aren’t using the UM role you can remove Desktop-Experience. Conclude after the restart by configuring the TCP Port Service to start automatically using (only CAS roles):
From the PowerShell, execute the command: Set-Service NetTcpPortSharing -StartupType Automatic

This prerequisites guide is not exhaustive, but you should now have all the prerequisites to installing Exchange 2010. Please let me know if you find any other prerequisites missing.

A great installation guide can be found here as well:

http://muc-ug.org.in/index.php/articles/exchange-2010/109-installing-exchange-server-2010.html

Exchange 2010 Installation Considerations Part 2

More requirements for Exchange 2010:

Your Forest is required to be running at Server 2008 R2 Forest Functional Level.

x64 based hardware is required.

There is no in-place upgrade for Exchange 2007 to 2010.

It’s always important to map out your network prior to installing servers.

Consider your existing infrastructure and the needs of the company.

Discuss your design and deployment goals for using Exchange 2010.

Review the order of your deployments and consider the physical network layout and network connection speeds.

The following table shows minimum CPU core requirements for Exchange 2010 components:

Exchange2010_Cores — Click image to enlarge

The following table shows the minimum memory requirements for Exchange 2010:

Exchange2010_Memory — Click Image to Enlarge

Exchange Server 2010 is available in two different editions: Standard and Enterprise

The edition is determined by the product key, however, when installing as a trial version it will be running as Enterprise Edition.

The Exchange Management tools can run on Windows 7, Windows Vista with Service Pack 2, Server 2008 SP2, Windows Server 2008 R2.

Standard Edition – Limited to 5 Databases per server

Enterprise Edition – Can run up to 100 databases per server (previous editions both standard and enterprise allow database availability groups (High Availability) but require cluster which require Enterprise Edition of Server 2008 Enterprise.

Client Access Licensing (CAL’s) also come with both Standard and Enterprise versions. Sometimes the type of license will limit clients. For example, mobile devices without the correct license may not be able to use certain features.

Prerequisites: Use the powershell commandlet or Server Roles and Features to install prerequisites. Different Exchange roles will have certain requirements. Eg. the UM role requires the Desktop Experience feature installed.

More Hardware Requirements:

Processor(s): x64 Intel or AMD

Memory: can change due to different role being installed, but typically 4GB min per server. If combining roles, 8GB. Add 2-10MB memory per mailbox. The maximum memory for a Mailbox role is 64GB

Disk Space: For the Mailbox Role, you will need a minimum of 1.2GB to install Exchange.

Need an Additional 500MB for each UM language pack
An Additional 500MB for the queue DB for the Edge or Hub Transport Role Server
Check out the MSFT exchange Calculator at www.msexchangeteam.com or you can download version 17.2 here: E2010Calcv17.2
Exchange 2010 Mailbox Server Role Requirements Calculator official blog post is here: http://blogs.technet.com/b/exchange/archive/2011/06/06/v17-2-of-the-e2010-mailbox-role-requirements-calculator-released.aspx

Server OS: Server 2008 or Server 2008 R2

Prerequisites for Server 2008 SP2

.NET Framework 3.5 SP1
Install the .NET Framework 3.5 Family Update
Windows Remote Management (WinRM) 2.0 here: http://support.microsoft.com/kb/968929
PowerShell v2
For Hub Transport and MailBox servers, install the MS Filter Pack. *Note: On Exchange 2010 RTM, you can meet the prerequisite by installing 2007 Office System Converter: Microsoft Filter Pack. However, MS recommends that you upgrade to the Microsoft Office 2010 Filter Packs.
From an elevated command prompt, from the Scripts folder, issue the following commands:

Sc config NetTCPPortSharing start auto
ServerMangerCmd -ip Exchange-Typical.xml -Restart

7. With the Unified Messaging role type:

ServerManagerCmd -i Desktop-Experience

Some useful tools in the scoping and stress testing of Exchange are:

1. Risk and Health Assessment Program for Exchange Server (ExRAP) – Scoping Tool v1.5 http://www.microsoft.com/download/en/details.aspx?id=20857

2. Planning and deployment guide: http://technet.microsoft.com/en-us/library/aa995902.aspx *Especially the Mailbox Server Storage Design

3. Install and run Jetstress on your hardware prior to deployment

The documentation for the Exchange Server 2010 version of Jetstress is available on TechNet at the following location.

http://technet.microsoft.com/en-us/library/ff706601.aspx

Version	Build	Usage	Link
14.01.0225.017	32 bit	Exchange 2003[1]	http://www.microsoft.com/downloads/en/details.aspx?FamilyID=6c9c1180-4dd8-49c4-85fe-ca1cdcb2453c&displayLang=us
14.01.0225.017	64 bit	Exchange 2007 Exchange 2010	http://www.microsoft.com/downloads/en/details.aspx?displaylang=en&FamilyID=13267027-8120-48ed-931b-29eb0aa52aa6

Table 1 – Jetstress version and download table

[1] Refer to Appendix D – Exchange 2003 for information on configuring Jetstress 14.01.225.x for Exchange 2003

A good majority of the content provided in my Blog’s Exchange series is derived from J. Peter Bruzzese’ excellent Train Signals Exchange Server 2010 Video Disk Series as well as my own Exchange 2010 lab. Trainsignal.com is an invaluable source for accurate, easy to understand, IT information and training. http://www.trainsignal.com

Exchange Server 2010 Overview Part 1

Microsoft’s Exchange Server:

Email is a mission critical tool for business. How do you provide that capability? Hosted, in-house, BPOS? There are many options. With Exchange you gain the following:

A reliable and flexible messaging platform for business communications.
Provides e-mail capabilities
Also provides calendar access and contact management
Users can have access to their communications anywhere; through their browser, mobile device, or their Outlook client.

Exchange 2010 adds the following:

Provides the email typical for Exchange that we’ve come to expect. Some features are the same as Exchange 2007, but new features are notable.
Continues the Server Roles for your organization’s deployment strategy. (5 Roles)
Includes High Availability and Site Resilience
Allows Unified Communications through the Unified Messaging Server Role that will give users a Universal Inbox (fax’s, voicemail, etc)

5 Server Roles: – Prior to Exchange Server 2010, you installed the entire Exchange infrastructure on an Exchange Server. Eg. if a Front-end server was only needed, you still had to install the entire Exchange Infrastructure. Now you have a lighter footprint with Roles. Server 2008 also uses Roles and Features.

The Mailbox Role: user mailboxes with mailbox DB’s. Also contains public folders.
Client Access Role: connection point for all users to their mailboxes internally or externally. (MAPI, OWA, Outlook Anywhere, ActiveSync, IMAP/POP)
Hub Transport Role: Flow of traffic to and from the Mailbox server. (These first 3 roles need to be installed in order for Exchange to work, but not necessarily on the same server.)
Optional Role – Unified Messaging Role: Provides the Universal Inbox for voicemail, email, faxes, etc.
Optional Role (recommended)- Edge Transport Role: Perimeter-based server to handle anti-spam and anti-virus protection and additional transport rules.

Requirments for Exchange 2010:

1. Domain Controller – AD Domain controller

2. DNS Services

3. Member Server (on which you will install Exchange)

For Exchange 2010 running behind your firewall or DMZ on your internal network, you can install the following 4 roles on their own server: Client Access Server, Mailbox Server, Hub Transport Server, and Unified Messaging Server.

To add an Edge Transport Server to your network, you will need to setup a Member Server that is not a member of the Domain. You install Exchange, but only the ET server role. This will sit out on the Perimeter Network (between internal and external firewalls – DMZ). Again, the ET server cannot be a member of the Domain.

New in Exchange 2010:

Storage Architecture – There’s a new focus on the database itself, not on a storage group. Storage groups have been removed from Exchange’s DB design (Exchange 2000 – 2007)

High Availability and Site Resiliency – Database Availability Groups have replaced legacy Exchange HA versions.

Permissions – Role-based access control has been implemented – permissions to manage exchange.

Control – A cool new Web-Based Exchange Control Panel (ECP). Carries over Exchange 2007’s exchange management console and an exchange management shell.

Voicemail and Unified Messaging – including voicemail preview, better protection.

Exchange 2010 has something for everyone. It is a complete communications platform for organizations large and small.

A good majority of the content provided in my Exchange series is derived from J. Peter Bruzzese’ excellent Train Signals Exchange Server 2010 Video Disk Series. Trainsignal.com is an invaluable source for accurate, easy to understand, IT information and training. http://www.trainsignal.com

Networking Fundamentals – Part 2

Repeater: A repeater’s job is to repeat an electrical signal. The form that our data has taken to be sent across a cable is one’s and zeros. The repeater takes an incoming signal and then generates a new clean copy of that exact signal. This prevents maximum cable lengths from stopping transmissions and helps ward off attenuation; the gradual weakening of a signal.

Hubs – only one PC at a time can send data; if multiple PC’s are connected to a single hub, it’s One Big Collision Domain. To prevent collisions, a host will use CSMA/CD (Carrier sense multiple access with collision detection).

CSMA/CD:

a carrier sensing scheme is used.
a transmitting data station that detects another signal while transmitting a frame, stops transmitting that frame, transmits a jam signal, and then waits for a random time interval before trying to send that frame again.

Bridge – used to create smaller collision domains. Place a bridge between multiple hubs. More collision domains is more beneficial. Segmenting the collision domains does not reduce the amount of broadcasts (for example, multiple hubs separated by multiple bridges is still one big broadcast domain). Every single host will receive a broadcast.

Broadcasts are not a bad thing, broadcasts can be beneficial by providing routing updates. But we do want to lower the number of broadcasts.

Switches: each host is in it’s own collision domain. Collisions cannot occur. Each host has more bandwidth available; not sharing bandwidth. Theoretically each host can run at 200mb (100mb sending, 100mb receiving with full duplex). Switches by default do not break up broadcast domains. Microsegmentation is a term sometimes used with Cisco documentation to describe the one host/one collision effect.

A switch will do one of three things with an incoming frame:

Forward it
Flood it
Filter it

The switch looks at it’s Mac address table to check if there is an entry for the destination MAC address, but first the switch will look to see if there’s an entry for the source MAC address in the frame. The switch uses the source MAC address to build the table. You can statically configure MAC address tables but not recommended.

#show mac-address-table — The command we use to look at the mac address table on a switch.

An unknown UNICAST frame is always flooded. – If an unknown unicast frame has to hit 79 other ports in an 80 port switch, it can cause a bit of overhead on the switch/cpu.

#show mac-address-table dynamic

If the switch does not have an entry for the destination mac address, and a host replies to the flood with the correct response, the switch will create an entry for the new host.

Take into consideration the following diagram:

SwitchFilterExample — click image to enlarge

In this instance, hosts A and B are in the same collision domain, separated by a hub. When Host A sends out a frame destined for Host B, and the frame arrives at the switch, the switch looks at it’s dynamic MAC address table and sees that the frame is destined for the same port as it’s origin. In this case the switch will FILTER the frame (drop the frame):

MacTableFilterExample — Click to enlarge image

Switches never send a frame back out the same port from which the frame arrived.

Flooding: When the switch has no entry for the frame’s destination MAC address. The frame is sent out every single port on the switch except the one it came in on. Unknown unicast frames are always flooded.

Forwarding: when the switch does have an entry for the frame’s destination MAC address. Forwarding a frame means the frame is being sent out only one port on the switch.

Filtering: when the switch has an entry for both the source and the destination MAC address; the MAC table indicates that both addresses are found on the same port. (See image above)

Broadcast frames: a frame that is sent out every port on the switch except the one that received it. Broadcast frames are intended for all hosts, and the MAC broadcast address is ff-ff-ff-ff-ff-ff.

We can statically configure a port with a MAC address but not best practice. Dynamically learned MAC addresses will age out with a default of 300 seconds (5 minutes).

Command to see help for the tables is

#mac-address-table ?

then

#mac-address-table aging-time ?

0-0 Enter 0 to disable aging (not a good thing to do)

10-1000000 Aging time in seconds

The benefit of Dynamically configured MAC addresses is that if the host is not seen in 5 minutes or the interface goes down; physical damage to the port, when the host is connected to a different port, the switch will dynamically update the table with the source. The current entry will be aged out. Let the switch do it’s work, and use dynamically assigned addresses.

When the switch forwards, floods, or filters the frame, there is another decision to be made – how will the forwarding be processed?

Three different processing options:

Store-And-Forward
Cut-Through
Fragment-Free

Store and Forward is the default method on newer switches. The entire frame is stored and then forwarded.

Store and Forward – uses FCS – allows the recipient of the frame to determine if the data was corrupted during transmission (error detection). In the incoming frame the switch will read the destination MAC address before it looks at the FCS. The switch can check the FCS before forwarding the incoming frame. Gives us more error detection than the other two methods above.

Cut-Through – switch reads the MAC addresses on the incoming frame, and immediately begins forwarding the frame before rest of the frame is even read. Cut through is a lot faster. Cannot check for damaged frames.

Fragment-Free (middle ground for speed vs. error detection) works on the presumption that the corruption will be found in the first 64 bytes of the frame for damage. If no damage, then the forwarding process will begin.

Use virtual LANs to segment a network into smaller broadcast domains. In a production network, you can have a lot of hosts and each host can send out broadcasts with a cumulative effects. Hosts tend to respond to Broadcasts with a Broadcast of their own.

Broadcast Storm: can max out a switch’s resources (memory and cpu) making the switch useless. But before this, broadcasts may take up most of the bandwidth.

Create multiple broadcast domains to limit the scope of a broadcasts.

Basic command to view vlans is

#show vlan

but for practical use, the command below is better:

#show vlan brief

By default, you will have a single vlan on modern cisco switches.

To put for example two hosts in a separate single vlan (broadcast domain),

#conf t

#interface fast 0/2

#description Connected to Host 2

#switchport access vlan 24

#switchport mode access — to makes access to only one vlan – no trunking

then

#int fast 0/4

#description Connected to Host 4

#switchport mode access

#switchport access vlan 24

#^Z

#copy run start

#show vlan brief

Once host2 and host4 are on the same vlan they won’t be able to ping other hosts on other vlans.

No traffic – pings or data packets can be sent from one VLAN to another without intervention of a Layer 3 device; most likely a router.

Networking Fundamentals – Part 1

In these posts, we will document the fundamentals of networking. We will begin with the basics, including the OSI model, and work our way up from Layer 1 to layer 7, but mostly concentrating on Layers 1-3.

As many have learned, the path to success in troubleshooting networks is knowing and understanding the fundamentals.

OSI (Open Systems Interconnection) model:

Layer 7: Application Layer:

End users are interacting with the layer itself. When a user is being authenticated, that user is interacting with layer 7. If encryption is taking place, that is layer 6. The application layer determines if a remote communication partner is ready. For example if a modem is in use, the application layer asks if the modem is ready. Agrees on procedures for communication; data integrity, privacy and error recovery. Protocols running at layer 7: SMTP, POP3, Telnet, HTTP, FTP, SNMP.

Layer 6: Presentation Layer:

Formatting of data. For example if Word opens a file in gobbly gook, that is a presentation layer issue. No agreement has been made for formating. Compatability with the OS, ASCII, Binary, compression. JPG, MIDI, TIFF. Any file type is how data is being presented.

Layer 5: Session Layer:

Handles creation, maintenace and tear down of communication between hosts. The communication itself between two hosts is called a session. Sessions can be short. The session layer manages communication. Provides Full Duplex, Half Duplex, or Simplex. The Session Layer is commonly implemented explicitly in application environments that use remote procedure calls.

Layer 4: Transport Layer:

Establishes end-to-end connection between two systems. Session data is received from the upper layers and the transport layer makes sure the data gets to the destination in the correct sequence, and without errors. TCP (Connection-oriented) and UDP (Connectionless) are two methods of transporting data at the Transport Layer.

Layer 3: Network Layer:

IP runs at this layer, routers at this layer (routing layer), IP addresses, layer addresses, etc. Routing is a two question process: Is it a Valid path? And what is the Best Path to get there?

Layer 2: Data Link Layer:

This is where our switches and bridges run. WAPS also operate at this layer. Cable modems/DSL modems. Ethernet, HDLC, PPP, Frame Relay. There is a big difference between error detection and error recovery. Layer 2, we have error detection with FDS Frame Detect Sequence. MAC addresses/Hardware addresses/Physical Addresses/Burned In Address (BIA) are at Layer 2. There is such a thing as a layer 3 switch; a single device that can do the routing and the switching.

Layer 1: Physical Layer:

1’s and 0’s. The Physical Layer handles the actual data being transmitted. Cables, pins, voltage running at physical layer.

TCP:

Guaranteed Deliver
Error detection via sequence and ACK numbers
Windowing
Connection Oriented

TCP Three-way handshake: SYN, SYN-ACK, ACK.

Error detection is finding an error.

Error recovery is doing something about the error.

For example some layers have error detection – layer 1, but not error recovery.

In transmitting several segments, when the recipient sends the ACK number, it sends the next number in the sequence that the recipient expects to receive. An acknowledgement timer will re-send: Positive Acknowledgement with Retransmission (PAR).

Windowing is the amount of data that the sender is allowed to transmit without waiting for an ACK. The recipient decides the size of the window. This gives the recipient the ability to decide the amount of data flow. (Flow Control) Sliding Windows refers to dynamic adjustment of the size of the window itself.

UDP:

Best effort delivery but no guarantee of delivery
No error detection
No windowing
“Connectionless”

Cables:

Crosstalk – EM interference; a signal crosses over from one cable to another. Can be described as Near End Cross Talk (NEXT) or Far End Cross Talk (FEXT) depending on which end of the cable is being tested. PSNEXT is Power Sum Near End Cross Talk which is the calculation made when a NEXT test is run. When the NEXT result for each pair of wires is added, the result is the PSNEXT. (Not to be confused with the management software titled PSNEXT).

Straightthrough cable – used to connect a PC to a switch or a hub. The wire connected to Pin 1 on one side is connected to Pin 1 on the other, the wire connected to Pin 2 on one side is connected to Pin 2 and so forth.

CrossOver Cable – typically used between two switches, and when two switches are transmitting data over the same pair of wires, a crossover cable is used. A switch to switch connection with a CrossOver Cable is also called a TRUNK.

Rollover Cable – All eight wires in the cable will “roll over” to another pin at the remote end. eg. Pin 1 at one end rolling over to pin 8 at the other end. Pin 2 rolling over to pin 7 etc. Typically Blue Cisco cables that come with each Cisco router with a DB9 connector are Rollover cables. (Get a USB adapter so that you can use it with your laptop). These cables typically connect to the console port on the switch/router.

MAC address – Media Access Control Address (Also known as Ethernet/NIC/LAN/Physical/BIA address): used by switches to send frames to the proper destination. 48bit address.

The MAC address has two parts, the first being the Organizationally Unique Identifer (OUI). The OUI is assigned to hardware vendors by the IEEE. A given OUI is assigned to one and only one vendor. The second half of the MAC address is a value not yet used by that particular vendor.

The Broadcast MAC address: 77-77-77-77-77-77

The Multicast MAC address always starts with 01-00-5E, then 00-00-00 thru 7F-FF-FF

Outlook 2010 – Cannot create new profile; An unknown error occurred, error code: 0x80070057 – Solved!

One of our Windows 7 Pro, 32 bit users (not SP1), experienced Outlook 2010 failing on a regular basis. The client was setup with Auto-discover and the application would crash / freeze/ hang randomly as well as could be made to crash by going into the Calendar, create a New Meeting->Scheduling Assistant -> and enter another user’s name.

Additionally, we tried closing Outlook, going to the Control Panel and chosing the Mail applet. Click on Profiles -> Profiles -> Show Profiles… -> Add…

The Outlook wizard would start, but then fail with the error message:

“An unknown error occurred, error code: 0x80070057”.

The Event Viewer (Local) -> (Windows Logs: Application) would have a cryptic message with the following information:

Event 1000, Application Error

Faulting application name: OUTLOOK.EXE, version: 14.0.4760.1000, time stamp: 0x4ba8fefdFaulting module name: OUTLOOK.EXE, version: 14.0.4760.1000, time stamp: 0x4ba8fefdException code: 0xc0000005Fault offset: 0x0054ac63Faulting process id: 0x1174Faulting application start time: 0x01cc0e56a826f1c7Faulting application path: C:Program FilesMicrosoft OfficeOffice14OUTLOOK.EXEFaulting module path: C:Program FilesMicrosoft OfficeOffice14OUTLOOK.EXEReport Id: 375d88cc-7a62-11e0-a74c-b8ac6fc5d92c

Running a search on these errors produced a lot of options for repairing the problem including checking OWA IIS certificates, installing .NET on the exchange server, Exchange SP2/SP3, editing your hosts file, Exchange PowerShell setting virtual directory, and the list goes on.

The solution that resolved this issue finally for us was to install on the Outlook client, the hotfix created by Microsoft here: http://support.microsoft.com/default.aspx?scid=kb;en-US;2281463

The download is not easily accessible on this page, so don’t be discouraged and go ahead and “View and request hotfix downloads” from the link at the top of the page.

This link will send you to a Hotfix Request page where you place a checkmark on the update you wish to download. Be careful because if you visit the page with a x64 machine, you will most likely be prompted to download the x64 client. It’s best to visit the hotfix page on the client that has the problem. Enter your email address and then confirm. Type in the captcha and then hit “Request hotfix.” You will be quickly emailed the link to the hotfix download as well as a password.

*Note: Prior to installing a hotfix of this nature, it is always recommended you backup your system (Windows 7 backup is a pretty good free image-based backup, my next best recommendation is something like Acronis 10.) Also, it is a good idea to take a manual System Restore point: Start -> Right-click on Computer, choose Properties, System Protection, Create.

Once the hotfix has been downloaded, when you try to run the .exe you will be prompted for the password for the file to run. Enter the password that was emailed to you and complete the setup. After the hotfix completes, for good measure, go ahead and reboot. After the restart, keep Outlook closed and go back to the Mail control panel applet. Go to Profiles ->Show Profiles… -> Add… and create a new Outlook Profile. Under “When starting Microsoft Outlook, use the profile: -> Always use this profile -> Hit the dropdown for the newly created profile.

Start Outlook. This will create a new Outlook profile for the user. Also, a new .ost file will be created which if the mailbox size is large, it may take a considerable amount of time to rebuilt the new profile. You may need to visit the old profile in the Control Panel Mail Applet to see if any data files were attached or settings/signatures were modified or need to be created or copied to the new profile.

You can test to see if the application crashes by visiting the Calendar Scheduling Assistant.

SBS Server 2003 network connection NIC unresponsive. Solved!

After several restarts/reboots, a Small Business Server 2003 would not respond to pings, and was holding a network hostage by not servicing DNS requests. When trying to repair the Local Area Connection, the following error occurred: “Windows could not finish repairing the problem because the following action cannot be completed:
Clearing the ARP cache”

After starting/stopping the Routing and Remote services service, and disabling/enabling the NIC in the Device Manager with no luck, we tried manually clearing the arp cache with the following actions:

Check the ARP table from the command line with the command:

arp -g

See if there are entries, and if so, delete them with the command:

arp -d *

This did not help and what did resolve/solve the issue was the following actions:

Shut down the server (Start -> Shutdown)
Once the server has completely shut down, remove the CAT5 Ethernet cable(s) from the Network Interface Card in the back of the server. Make a note which NIC port(s) the cable(s) are plugged into if there is more than one.
Remove the power cable(s) from the back of the server. With both the power and Ethernet cables unplugged, press the power button on server to flush all electricity from the motherboard and interface cards.
Replace the power and Ethernet cables, and power up/start the server normally. In our case the server began responding to pings and started running normally.
After logging in, check to see that all services have started that are set to Automatic. To do this, go to Start -> Administrative Tools -> Services. Sort services by Startup Type. All of the services with the Startup Type: Automatic should be in the “Started” status (except for some that normally stay stopped like Performance Logs and .NET services).

Hopefully this tip will save you some frustration from wrestling with a non-responsive NIC or hunting down Microsoft hotfix updates.

A final note that if the unresponsive server is your primary DNS/DHCP server, and while it’s down clients are unable to get out to the internet or contact other network resources, you may wish to modify your DHCP client lease settings to include some (external) DNS servers other than your primary DNS/DHCP server.