Windows Server, Cisco Networking, and other IT Pro Stuff

Review of Windows 8 Developer Preview

2012-02-13T06:00:00.000-05:00

The Windows 8 Developer Preview shows off the Metro interface. From the preview, we can get an idea of where the Windows interface will be heading in the future. The future is not your Grandma’s (or Grandpa’s) Windows. See all screenshots in last weeks post Windows 8 Developer Preview Screenshots.

Install
Right away, during install, you’ll begin to notice differences between Windows 8 and previous installers. It seems in this case, simple is best. Abandoning any fancy progress indicators or background vistas (smile), we instead see a pleasingly green background with white font.

Aside from the difference in styles, the setup process is nearly identical to the one you’re used to with Windows Vista or Windows 7.

Logon
The final step of setup is to logon with a previously created account, or create a new account. This is where there’s a significant difference to previous versions. Here you have the option of using your pre-existing Windows Live ID. If you don’t have one, you also have the option of creating a new one.

Start Screen
When 8 finishes syncing your Live ID account, you will finally arrive at the Start Screen. No that’s not a typo, I didn’t mean to say Start Menu. The new Start Screen takes up the entire screen and scrolls horizontally. The best comparison for this experience is that it acts very similar to the File Menu commonly seen in Office 2010 where the full screen is used with a plethora of options.

Rather than displaying a list of text with small icons, the Start Screen uses tiles. The tiles have a wide array of uses. Simple single clicking a tile launches the program. Right clicking the tile provides additional options for the display of the tile, and in some cases, an option to uninstall the program.

Desktop
One of the options on the Start Screen is to go to the desktop. The desktop will seem like a safe place to users new to Windows 8 as it’s nearly identical to Vista and Windows 7. That is, until you click Start. Clicking Start will put you back to the Start Screen.

Accessing Windows Explorer from the Start Screen will also take you to the Desktop with Windows Explorer open.

More Ribbons
The ribbon feature that started in Office 2007, has come to fruition in Windows 8. For example, Windows Explorer now features the ribbon interface with it’s tabs and contextual tabs. Just like with the transition from Office 2003 to Office 2007, adding the ribbon in Windows 8 helps cleanup the interface. As someone who has spent a lot of time teaching Office classes to my staff, I see the added ribbons as a small but significant improvement because it adds uniformity to the user’s experience.

Navigation
When opening some of the programs using the Start Screen, you’ll quickly realize that the window resizing and closing buttons are not present at the top right. You also won’t see any kind of menus or tabs that can be used to access more options or simply close the application.

Instead, edges and unused areas of the application window are used to access additional program options or to change to another program. The average user will find it somewhat challenging to get used to this concept, but I think the direction this takes the user experience is interesting. A user will be encouraged and much more enabled to eliminate the number of user clicks or keystrokes needed to move between applications.

This may help with the user education gap by stripping away some of the options. Many of us have seen those users that still seem to think that only one program can be maximized at a time. Rather than simply using Alt+Tab or clicking the application in the task bar, they will go to great lengths to make sure every application is minimized before opening another.

Using Alt+Tab and WindowsKey+Tab still work.

My Opinion
While evaluating the new operating system, I was reminded of the last time I had to usher users from Windows XP to Windows Vista. At the time, the changes to the interface seemed drastic.
With that in mind, I can see that it’s going to be very challenging for IT shops to get their users up to speed. In the XP to Vista upgrade, I spent countless hours in formal training and helpdesk calls getting user’s acquainted.

Windows 8 Developer Preview Screenshots

2012-02-09T09:12:00.000-05:00

Booting

Name your PC, feels a little like Ubuntu setup

Logon with Live ID account

Finally...

Start Screen with Tiles

Updated Task Manager

Edge highlighted in red and Alt+Tab

Tile-ized Control Panel

Locked Screen

Exchange Management Console 2010 Initialization Failed

2012-02-07T06:43:00.000-05:00

Problem: When you open Exchange Management Console 2010 you receive an error message indicating that Initialization failed. Solution: ...

A while back I blogged about initialization failed when trying to open Exchange Management Console or Exchange Management Shell.

I ran into this problem again in a lab environment and this time just running winrm quickconfig and iisreset it still didn't work.

Initialization Failed: Connecting to remote server failed with the following error message : The WinRM client sent a request to an HTTP server a got a response saying the requested HTTP URL was not available. This is usually returned by a HTTP server that does not support the WS-Management protocol. For more information, see the4 about_Remote_Troubleshooting Help topic.

This time I had something wrong with IIS bindings for port 80. After correcting the binding and running iisreset, EMC and EMS worked again.

Also some good information here http://social.technet.microsoft.com/Forums/en-US/exchange2010/thread/58d46df7-4c64-4cd8-b394-08304bc4601e and here http://blogs.technet.com/b/exchange/archive/2010/02/04/3409289.aspx

Configure NTP on Windows Server 2008 R2

2012-02-02T09:54:00.000-05:00

http://www.sysadminlab.net/windows/configuring-ntp-on-windows-2008-r2

Great article on configuring NTP for Windows Server 2008 R2.
Especially useful when your Domain Controller is running Core edition.

DNS waiting for notification from AD DS

2012-02-01T06:33:00.000-05:00

http://blogs.technet.com/b/ad/archive/2007/04/29/adroitly-sidestepping-initial-synchronization-requirements.aspx

When a domain controller is restarted the AD-integrated DNS waits for notification from AD DS that it is in sync before DNS works. This is problematic when all other DCs are down and/or count on the DC to get other supporting systems operational (like in virtualized environments).

The quick and easy remedy to this is to create a registry entry disabling this feature.

The main purpose of this feature is to assure that FSMO changes while a DC is offline are not screwed up by the DC coming back up and thinking it should still hold one of those roles.

For example, say DC1 was down for a month. During that time other DCs were used to seize the roles that DC1 held. Without this check, DC1 could come online and attempt to continue to assume those FSMO roles.

In short, the reg entry should be used to allow a DC to fully come back online when you know there have not been any changes. Once that server is operation, the registry entry should be removed so that it doesn't cause problems further down the road.

Cisco Network Monitoring Part 3: IP SLA

2012-01-31T06:30:00.000-05:00

What is it?

IP SLA, or Cisco IOS IP Service Level Agreement, is a feature allowing a network administrator to monitor Cisco network devices. IP SLA can be used to moniter a variety of different performance and availability metrics including jitter, latency, and network and server response times. (Cisco IOS IP Service Level Agreement Q&A)

How does it work?

IP SLA, which can be secured using MD5, uses two components, a source and a responder who communicate over UDP port 1967. The source is the device being used to query other devices for information. The responder is simply the device(s) that responds to the source. Cisco gear typically will respond to source queries without additional configuration. In some cases, the hardware needs to be configured to be a responder through the ip sla monitor responder global config command.

An SLA can also be referenced by a track object and and used to automate recovery and failover.

Because timestamps are involved, source and responder should be synchornized using an NTP time source.

Measurement Metrics: Latency, Packet Loss, Network Jitter, Distribution of Statistics, Connectivity.

Operations: Jitter, FTP, DNS, DHCP, DLSW, ICMP, UDP, TCP

How to configure?

A basic use for IP SLA is using pings to monitor another piece of hardware.

ip sla monitor 5 (define a monitor by number)
type echo protocol ipIcmpEcho 172.16.1.1 source-interface FastEthernet0/0 (specify how monitor will work by setting type, protocol, IP to ping, and source interface to use)
frequency 10 ( number of seconds between each probe)
ip sla monitor schedule 5 life forever start-time now (schedule SLA to begin now and run indefinitely)
track 1 ip sla 5 reachability (create a tracking object that uses SLA monitor 5 and track reachability)

How to verify?

To verify configuration and view statistics use some of the following show commands.

show ip sla configuration
show ip sla statistics
show ip sla monitor configuration (older models)
show ip sla monitor statistics (older models)

Cisco Network Monitoring Part 2: SNMP

2012-01-27T07:07:00.000-05:00

Of the various flavors of SNMP (v1, v2, v2c, v3), SNMPv2c defined by RFC 1901 is the most commonly used.

There are four components that make up SNMP

Manager - aka SNMP server, polls SNMP agents. stores, displays, and correlates information. Example: in a small or test environment, could be a Windows workstation with Spiceworks which has SNMP built in for monitoring.
SNMP Protocol - uses UDP to communicate. Typically the manager polls agents over UDP port 161. If traps are setup and the agent sends communication to the manager, it will use UDP port 162. If used of TLS or DTLS, ports 10161 and 10162 are used respectively.
Agents - gathers information and holds. Responds to manager requests for information. If traps are setup, will send traps when triggered.
MIB - short for Management Information Base. database of variables that identify information. Typically has a read and write community string.

SNMPv1
In the SNMP Protocol there are some different types of data transfer. Let's start with SNMPv1.

Get Request - requests value of MIB variable from agent
Get Next Request - after initial Get Request, retrieve next object instance
Set Request - set MIB variable on an agent
Get Response - agent respond to Get Request or Get Next Request from manager
Trap - used by agent to actively send alarm to manager. Typically, manager initiates communication, but a trap is triggered by the agent. An example could be a trap that is triggered when an interface goes down.

SNMPv1 used 32-bit counters.

SNMPv2 added two new messages.

Get Bulk Request - used for repetitive requests and replies to improve performance
Inform Request - unlike Traps which are unconfirmed, the network management system acknowledges an Inform Request

SNMPv2 also added data types with 64-bit counters.

SNMPv3 adds levels of security so that SNMP traffic can be authenticated and encrypted.

noAuthNoPriv - no authentication and no encryption
authNoPriv - authentication through HMAC-MD5 or HMAC-SHA, no encryption
authPriv - authentication through HMAC-MD5 or HMAC-SHA, encryption through CBC-DES

Sample Configuration from global config

access-list 100 permit ip 172.16.1.0 0.0.0.255 any
snmp-server community renamedpublic RO 100
snmp-server community renamedprivate RW 100
snmp-server trap 172.16.1.150

Here's how to configure SNMP. Refer to Cisco's website for more configuration examples.

SNMP Configuration Examples: http://www.cisco.com/en/US/docs/ios/12_2/configfun/configuration/guide/fcf014.html#wp1001599
Cisco SNMP http://www.cisco.com/en/US/tech/tk648/tk362/tk605/tsd_technology_support_sub-protocol_home.html
Wikipedia SNMP http://en.wikipedia.org/wiki/Simple_Network_Management_Protocol

Cisco network monitoring tools part 1: Syslog

2012-01-23T07:00:00.003-05:00

In this series of three articles, I'll explain three methods of monitoring Cisco gear using Syslog, SNMP, and IP SLA. This is helpful study material for a CCNP SWITCH candidate. These monitoring methods are also very helpful for any network administrator.

Syslog
Syslog is a method of logging information on Cisco gear. It uses plain English and can report to a console connection, monitor connection (Telnet or SSH), system buffer, or remote syslog server over UDP port 514.

Syslog messages consist of 8 different levels (0-7).

Emergency (0)
Alert (1)
Critical (2)
Error (3)
Warning (4)
Notice (5)
Informational (6)
Debugging (7)

Syslog messages also hold to a distinct format.
The first part of the message includes a %Facility-Subfacility. This is often %SYS for notifications of changes from the console. The second part contains the severity level. Third is the Mnemonic code uniquely identifying the error message. The fourth part is the message text describing in more detail the log message. Messages are prepended by the time.

There are many facility-subfacility codes including CDP, DTP, DVLAN , IP, SNMP, etc.

To centralize log monitoring, I would suggest configuring Cisco gear to report syslog messages to a syslog server. There are many solutions out there but my favorite thus far is the free version of Solarwinds Kiwi Syslog Server.

Let's say you wanted a Cisco switch to send syslog messages to a syslog server at IP address 192.168.1.10. From a global command prompt, run logging 192.168.1.10. Configure this setting on all your Cisco gear and you'll be able to easily monitor all network equipment from a central location.

Tip for Getting More Organized: Don't - Michael Schrage - Harvard Business Review

2012-01-13T10:05:00.000-05:00

Tip for Getting More Organized: Don't - Michael Schrage - Harvard Business Review

What I thought was an interesting article against spending any time organizing.

It makes sense. Don't spend time in Outlook placing email into folders when you can use Search and Search Folders to do it for you.

Slow Logons: The 3-headed monster

2012-01-08T08:44:00.003-05:00

Article I wrote for 4sysops.com

http://4sysops.com/archives/troubleshoot-slow-logon-part-2-the-3-headed-monster/

Troubleshoot slow logons - Part 1: Profile Size

2012-01-08T08:42:00.000-05:00

Article I wrote for 4sysops.com.

http://4sysops.com/archives/troubleshoot-slow-logon-part-1-profile-size/

Troubleshooting Exchange eDiscovery Errors Due to Lack of Full Access Permission

2011-12-16T16:26:00.003-05:00

New article I authored at 4sysops.com

http://4sysops.com/archives/troubleshooting-exchange-ediscovery-errors-due-to-lack-of-full-access-permission/

GNS3 setup and SDM

2011-12-15T15:03:00.000-05:00

Great blog article outlining complete configuration of GNS3 including connecting to virtual routers using SDM.

http://subnettingmadeeasy.blogspot.com/2007/12/gns-configuration-guide.html

Mailbox exceeded maximum number of corrupted items

2011-11-25T11:01:00.001-05:00

New article I authored at 4sysops.com about troubleshooting eDiscovery.

http://4sysops.com/archives/troubleshoot-exchange-ediscovery-this-mailbox-exceeded-the-maximum-number-of-corrupted-items/

Hyper-V and Dynamic Memory in Depth Video

2011-11-22T11:32:00.001-05:00

Great free video about dynamic memory in Server 2008 R2 Hyper-V.

http://channel9.msdn.com/Events/TechEd/NorthAmerica/2010/VIR304

MapiExceptionADNotFound: Unable to mount database

2011-10-31T12:08:00.000-04:00

I've seen this error message a few times while in the process of creating a new storage group and database in a clustered Exchange 2007 environment.

It seems to happen when the storage group is in a failed state and the new database has not yet been mounted. The natural thing to do is to attempt to initiate replication to show a Healthy state or to try to mount the database. Unforteunately, both attempts cause the MapiExceptionADNotFound error.

While I never did figure out the exact cause I did find an simple and easy workaround.

Place the storage group in the Suspended state.
Mount the database
Resume replication

Additionally, the Exchange Servers group needs Read permission to the Share on each node.

Lists, Lists, and more Cisco Lists

2011-10-29T15:11:00.001-04:00

I was recently studying for the CCNP ROUTE exam and wanted to clarify the different lists by comparing and contrasting. Also very important is when it’s appropriate to use each of them. Access lists area by far the most commonly known lists in the Cisco world. But there are also others and if you don’t use them often it can be tricky to recall the intricacies of each.

Here are the lists I’ll be definining:

access-list
prefix-list
distribute-list
offset-list

Access-lists

By far the most common use for an access-list in Cisco is filtering traffic inbound or outbound on a port. The two most commonly used access-list types are the standard and extended lists. Standard can be easily identified by the access-list number being in the range 1-99. Extended lists are in the range 100-199. Standard and extended lists allow inserting entries by using a sequence number. In addition to numbered lists, named lists can also be created. When creating the access-list that way, the entry of list entries varies slightly but using numbered or named lists both provide identical results.

Standard access-lists, perform OSI layer 3 comparison only. Simply stated, it only compares the IP address of the source traffic.

Extended access-lists can provide filtering for other OSI layers by specifying a different protocol type and port numbers. The extended list also provides the ability to check the destination of the source traffic.

Access-lists can be referenced by distribute-lists (EIGRP, OSPF, BGP, RIP), route-maps, offset-lists (EIGRP, RIP),

Standard Numbered
Let’s start with an example of a standard numbered list and we’ll assume we are going to filter incoming traffic on interface f0/0 on router R1.

This sequence creates access-list 1 and denies the host 192.168.1.1. The second entry added to the list permits all other traffic. If this is not added, all traffic would be denied as every list has an implicit deny any statement at the end. Because entries are evaluated in order until there is a match, the permit any will always match before the implied deny any. At interface FastEthernet0/0, the command ip access-group 1 in applies access-list 1 to the incoming traffic. Finally, showing access-list 1 provides the full list of entries. If there were matches, that would be shown for each line. Notice that without specifying sequence numbers, the router automatically increments by 10 for each entry. More on sequence numbers in the next example.

R1(config)#access-list 1 deny host 192.168.1.1
R1(config)#access-list 1 permit any
R1(config)#int f0/0
R1(config-if)#ip access-group 1 in
R1#sh access-list 1
Standard IP access list 1
   10 deny   192.168.1.1
   20 permit any

Standard Named

The named standard list gives the advantage of using words to identify access-lists which can make administration a little easier. As mentioned before, a named list accomplishes the same results as a numbered list. To create a named list, the commands used are slightly different. Line 1 below shows the creation of an ip access-list called Demo1. You’ll notice that the prompt is a little different once you press Enter. You are now in access-list configuration mode for Demo1 and can simply type deny or permit and then provide the key word any, host, or specify a network.

The example below shows a deny for host 192.168.1.1 and host 192.168.1.2. Then the list denies the subnet 172.16.1.0 with a wildcard mask that specifies that the first 3 octets should be examined during filtering. The last octet can be any number. The permit any should look familiar.

Following that I added another deny. You’ll notice the sequence number preceding the deny statement. Without that sequence number, the statement would have been added to the end of the list. That would not work since the permit any would match first and no more access-list entries would be examined. To insert the entry in an appropriate place, the sequence number is required.

The command at interface FastEthernet0/0, is very similar the one shown previously. The only difference is the command references the access-list using it’s name Demo1. Showing the access-list shows the results of this list. Again, if there were matches, that would be shown in parenthesis on the same line as the entry matched.

R1(config)#ip access-list standard Demo1
R1(config-std-nacl)#deny host 192.168.1.1
R1(config-std-nacl)#deny host 192.168.1.2
R1(config-std-nacl)#deny 172.16.1.0 0.0.0.255
R1(config-std-nacl)#permit any
R1(config-std-nacl)#25 deny host 192.168.1.3
R1(config-if)#ip access-group Demo1 in
R1#sh access-list Demo1
Standard IP access list Demo1
   10 deny   192.168.1.1
   20 deny   192.168.1.2
   25 deny   192.168.1.3
   30 deny   172.16.1.0, wildcard bits 0.0.0.255
   40 permit any

Extended Numbered and Named

I won’t go into great detail on the named list again as there are not any differences between standard and extended. The primary most evident change compared with the standard list is the ability so filter based on the destination of source traffic using the any, host, or subnet with wildcard mask.

The extended list also adds is the ability to filter based on protocol and port number. If we type access-list 101 permit ? at a global config we see an extensive list of protocols to choose from. If we take a look at using tcp, we can also see that specific ports can be specified.

R1(config)#access-list 101 permit ?
<0-255> An IP protocol number
ahp      Authentication Header Protocol
eigrp    Cisco's EIGRP routing protocol
esp      Encapsulation Security Payload
gre      Cisco's GRE tunneling
icmp     Internet Control Message Protocol
igmp     Internet Gateway Message Protocol
ip       Any Internet Protocol
ipinip   IP in IP tunneling
nos      KA9Q NOS compatible IP over IP tunneling
ospf     OSPF routing protocol
pcp      Payload Compression Protocol
pim      Protocol Independent Multicast
tcp      Transmission Control Protocol
udp      User Datagram Protocol

R1(config)#access-list 101 permit tcp any eq ?
<0-65535>    Port number
bgp          Border Gateway Protocol (179)
chargen      Character generator (19)
cmd          Remote commands (rcmd, 514)
daytime      Daytime (13)
discard      Discard (9)
domain       Domain Name Service (53)
drip         Dynamic Routing Information Protocol (3949)
echo         Echo (7)
exec         Exec (rsh, 512)
finger       Finger (79)
ftp          File Transfer Protocol (21)
ftp-data     FTP data connections (20)
gopher       Gopher (70)
hostname     NIC hostname server (101)
ident        Ident Protocol (113)
irc          Internet Relay Chat (194)
...

In addition to being able to specify a port, the range keyword can be used to specify a range of ports which can make the extended access lists very concise. One feature unavailable in access-lists is the ablity to specify a range of subnets in one command.   The solution for that is the prefix-list discussed next.

Below is a sample configuration for an access-list used to filter out http traffic destined to subnet 10.1.1.0/24 port 8000-9000. The first line deny tcp port 80 traffic from any source when destined for network 10.1.1.0/24 with destination port in the range 8000 to 9000. The next line permits all other IP traffic. Viewing the access-list we see information nearly identical to the standard list.

Finally, the access-list is applied the same was a the standard list to an interface.

R1(config)#$ access-list 101 deny tcp any eq www 10.1.1.0 0.0.0.255 range 8000 9000
R1(config)#access-list 101 permit ip any any
R1(config)#do sh access-list 101
Extended IP access list 101
   10 deny tcp any eq www 10.1.1.0 0.0.0.255 range 8000 9000
   20 permit ip any any
R1(config)#interface f0/0
R1(config-if)#ip access-group 101 in

This concludes the discussion of the Cisco access-list. In the next blog, we’ll explore how the access-list can be used for more than just filtering traffic on an interface.

Prefix-list

The prefix list functions similar to a standard access-list adding the ability to specify a range of subnets for a given network. Like a numbered access-list, the prefix-list is configured at the global config prompt. Like a named access-list, the prefix-list is referced by a name. A prefix-list would be referred to by the distribute-list command (EIGRP, OSPF, BGP, RIP), a route-map, or a crypto map match ip address prefix-list command. They also provide the ability to use sequence numbers to be able insert entries within the list. Processing is done starting at sequence number 1 and stops at the first match.

The real power of the prefix-list lies in the ability to use the ge and le parameters to specify a range of subnet mask bits.

In this configuration we have a prefix-list being created that will later be used to control which networks, received via EIGRP, are entered into the routing table. The first line says includes several items. FIrst of all is the name of the prefix-list Demo2. Next the permit 172.16.0.0/16 specifies that the entry is looking for 172.16.0.0/16 as a starting point. Finally the ge 20 and le 24 further specify that the number of bits should be greater than or equal to 20 and less than or equal to 24. Some examples of subnets that would match are 172.16.1.0/24 and 172.16.16.0/20. Examples of networks that would not apply are 172.16.1.0/30 and 172.16.128.0/17.

The second line prevents any subnet with 192.168 for the first 16 bits and mask with 24 bits or more. The final line matches all other routes as the 0.0.0.0/0 le 32 means any route that has less than or equal to 32 bits in the subnet mask.

R1(config)#ip prefix-list Demo2 permit 172.16.0.0/16 ge 20 le 24
R1(config)#ip prefix-list Demo2 deny 192.168.0.0/16 ge 24
R1(config)#ip prefix-list Demo2 permit 0.0.0.0/0 le 32

A distibute-list command in a routing protocols configuration mode would look similar to the following.

R1(config-router)#distribute-list prefix Demo2 in

Distribute-List

The distribute-list command is used within a routing protocols configuration mode to control which networks received by the routing protocol are eligible for the routing table or which networks are sent into the autonomous system by the router. It can also be used in redistribution of one routing protocol into another.

The distribute-list command can also be applied only to a specific interface. This may seem very similar to applying an access-list to an interface but is in fact much different. While the access-list would filter all traffic, the distribute-list only applies to networks advertised or received via that interface with the routing protocol where the distribute-list command is used. The command itself is also much different. The access-list is applied in the interface configuration mode. The distribute-list is applied to a routing protocol in the given routing protocol’s configuration mode.

Another key difference is that interface filtering references an access-list (ACL), whereas a distribute list can reference an ACL, prefix-list, or route-map.

Let’s take the configuration we left of with when discussing prefix-lists. The distribute-list command could be expanded so that a router will never add a route to a given network out a particular interface.   So let’s say we are recieving updates on f0/0 and f0/1 and we want to force the router to only have routes to network 10.1.1.0/24 going out f0/1. We could use the following configuration to accomplish this.

The first line shows a couple aspects not shown in the earlier configuration. The parameter seq 5 has been added to cause this entry to have sequence number 5. By default, entries are added started at 5 in increments of 5. At the end of the statement there is not a ge or le. This simply indicates that the entry should match network 10.1.1.0/24 exactly. Then in the EIGRP configuration, we specify that the distribute-list command filter incoming updates from interface FastEthernet0/0 using prefix-list Demo3.

R1(config)#ip prefix-list Demo3 seq 5 deny 10.1.1.0/24
R1(config)#router eigrp 1
R1(config-router)#distribute-list prefix Demo3 in f0/0

One important caveat for distribute-list with the in parameter. With RIP, EIGRP, and BGP, the the in filtering prevents those networks from being received by the routing protocol. OSPF is different. OSPF will continue to receive those networks. However; those networks are prevented from being entered into the routing table. This can be an important distinction to be aware of if you are concerned with processor overhead.

Offset-lists

Offset-lists can be used in EIGRP and RIP. The offset-list is used to add a value to the metric on a give interface. For RIP this adds hops to the hop count, and for EIGRP adds a value to the feasible distance (FD). The offset-list references an ACL to define interesting traffic. The offset can be adding to incoming and outgoing updates. Specifying a specific interface can isolate the affect to only a single interface. The absence of an interface applies to all matching updates.

Here’s an example in EIGRP. The first three lines are just defining an access-list that will deny 10.1.1.0/24, permit all other 10.0.0.0 networks, and deny all other traffic. The permit and deny can be tricky. The permit or deny is including or excluding traffic from having the offset added. This does not change which updates participating in the routing protocol. In that aspect, the offset-list is much different than the distribute-list. In router configuration, the offset-list command specifies access-list 1, applied to incoming updates, adding a metric of 10, when the incoming interface is fa0/0. The result is that any 10.0.0.0 networks not 10.1.1.0/24 will have 10 added to their metric. Let’s say that R1 also receives 10.0.0.0/8 from interface f0/1. Because the same network has a higher metric via f0/0, the router will select f0/1 as the outgoing interface for that network.

R1(config)#access-list 1 deny 10.1.1.0 0.0.0.255
R1(config)#access-list 1 permit 10.0.0.0 0.255.255.255
R1(config)#access-list 1 deny any
R1(config)#router eigrp 1
R1(config-router)#offset-list 1 in 10 fastethernet0/0

eDiscovery in Exchange Part 5 - Export and search

2011-10-26T08:47:00.000-04:00

Final post of 5 part series on eDiscovery in Exchange.
http://4sysops.com/archives/ediscovery-in-exchange-part-5-export-and-search/

2011-10-21T07:22:00.000-04:00

Great resource for learning and reviewing IPv6 for the CCNP Route Exam.
http://www.youtube.com/user/Keith6783

eDiscovery in Exchange Part 4: Restoring a mailbox database with DPM 2010

2011-10-11T15:27:00.002-04:00

http://4sysops.com/archives/ediscovery-in-exchange-part-4-restoring-a-mailbox-database-with-dpm-2010/

eDiscovery in Exchange Part 2 and 3

2011-09-30T13:28:00.001-04:00

eDiscovery in Exchange Part 2 and 3 at 4sysops.com
http://4sysops.com/archives/series/ediscovery-in-exchange/

Switch Port Monitoring

2011-09-23T09:16:00.003-04:00

Nice page about configuring Cisco port monitoring on various models.

http://www.securitywizardry.com/index.php/tools/switchport.html

eDiscovery in Exchange Part 1 - Introduction

2011-09-16T16:00:00.003-04:00

http://4sysops.com/archives/ediscovery-in-exchange-part-1-introduction/

Windows Server Core Edition

2011-09-08T13:44:00.001-04:00

Windows Server Core Edition is definitely valuable to command line gurus that can make it sing.
But some of us just don't do that every day. I've found that it can be hard to locate helpful information to accomplish certain tasks like allowing Remote Server Administration Tools to connect when neither server is part of a domain.

I found a nice article about Core. What's even more helpful are all the related links with tons more information in each related link. Keep following related links in those and there is a lot of info that will go towards a better understanding of how to, as one put it, "get dirty" with Windows Server Core Edition.

http://searchwindowsserver.techtarget.com/tip/Four-Server-Core-myths-Busted?asrc=EM_NLT_14820581&track=NL-1687&ad=846699

Single Inbox in Cisco Unity Connection 8.5 with Microsoft Exchange - Part 2

2011-09-06T09:41:00.002-04:00

Article I wrote for 4sysops.com

http://4sysops.com/archives/single-inbox-in-cisco-unity-connection-8-5-with-microsoft-exchange-part-2/