ip helper-address Not working on Cisco 3750 Switch

July 1st, 2010

I had a cisco 3750 switch that i wanted to enable some vlans for voice on, but only having one DHCP server on a completely seperate vlan to the voice vlans.

vlan 1 = data (dhcp server on this range)

vlan 266 = voice (phone dhcp clients on this range)

The switch for some reason had aload of dhcp server config on it before i started the exercise, so i removed the pools and ran the command: no service dhcp

This was the problem, running this command (no service dhcp) disables dhcp but also disables dhcp relay to, this stops the ip helper-address command from working too.

So even when i put the ip-helper address on the vlan as below it didn’t relay the dhcp broadcasts from the 266 vlan to the dhcp server on vlan 1.

interface Vlan266
 description *** VOIP-BBlock ***
 ip address 172.29.66.1 255.255.255.0
 ip helper-address 172.19.5.131

Where 172.19.5.131 is the DHCP server address.

Cisco Information Link

So to fix it, i ran the command: service dhcp

(making sure any dhcp pool configuration has been removed, and this fixed the problem)

Documents freezing on load in Microsoft Word 2003

April 21st, 2010

Here was a weird one, Word 2003 froze on startup, opening the document in word 2007 was the key to it, in the bottom left, it flashed up trying to connect to \\servername\folder\test.dot. Hmm in our case the servername was the name of a server that had been decommissioned! WOrd 2007 allows you to hit ESC to abort this. Word 2003 just freezes up.

The resolution is to stip this out of the file, either by using WOrd 2007 or by using the link belows solutions:

http://support.microsoft.com/default.aspx?scid=kb;EN-US;830561

Microsoft DPM 2007 (ID 998 Details: An existing connection was forcibly closed by the remote host (0×80072746))

April 21st, 2010

The operation failed because of a protection agent failure. (ID 998 Details:
An existing connection was forcibly closed by the remote host (0×80072746))

Had this problem occouring when trying backup to tape.

The majority of the tape backup jobs worked fine, then on two of the disks on two of the servers it kept failing
interestingly failing at about the same place. In our case at 3.5GB on one disk and 700MB on the other.

After getting Dell to replace the TL2000, upgraded firmware for the library and the drive, used the latest drivers from DEll and
from IBM as its a IBM rebranded library and drive still the same problem.

Patched up all the hotfixes i could find at the time, SP1 of DPM 2007 too. Still no joy.

This doesn’t make sense as the backup is from the DPM replica to tape, it is NOT connecting to the original host.

I was with our Anti-virus guy (Kaspersky) and was discussing the problem, although i’d given him the list of the DPM volume
mount points used to exclude from the scan the AV software still scanned the replica and volume shadow copies on the DPM server.

I retried the failed job and waiting, about 5 seconds before the tape job failed the AV detected 3 virsues on the disk and tried
to delete them, as its in a volume mount point, it couldn’t and therefore blocked access, 10 seconds later the tape backup job reported failed.

So that was it the AV was causing the problem. Removed the AV software (to test) and reran the job went through no problems.

Now we have working backups the challenge is to get them to work with the AV installed (Kaspersky in our case)

DPM 2007 – Volume Missing

February 27th, 2010

After a power cut, (before the UPS was installed!), on booting back up the DPM 2007 server, the server showed loads of replica disks saying “Volume Missing”, before i crying, it tried the following to get DPM to pick them back up and it appeared to work ok:

Run the command below to enable auto-detect of new volumes.

Mountvol /e

Rescan for disks in the COmputer Management Disk Management.

Then in DPM 2007 Console
DPM 2007 -> Management -> Disks -> Select DIsk 1
Click Rescan and wait.

Repeat for all the disks you have.

Then go back to the “monitoring” tab. And select alerts you should see all this missing disk alerts disappear. Once gone mop up any other warnings and run some synchs on the disks that were missing just to be sure. But that should resolve the problem.

WSUS – Computers reporting and then disappearing

February 9th, 2010

Reset WSUS ClientBeen working on WSUS and have setup a WSUS server. However started to get a problem whereby the computers were appearing on WSUS and reporting their status then disappearing. I noticed that they were disappearing and being replaced by another computer.

It turns out that when a machine is ghosted and then sysprep’ed it doesnt reset the WSUS id, which is a unique ID that WSUS uses to track the computer. So i’ve been able to come up with a script that can be run manually or via a script (GPO) on startup to reset this ID and make it talk properly to WSUS. Note this also sorted problems with Virtual Machines that have been cloned too.

Set oShell = CreateObject(”WScript.Shell”)

sRegKey = “HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate”
pRegKey = “HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Connections”

‘ suppress error in case values does not exist
On Error Resume Next

‘ check for marker
sIDDeleted = oShell.RegRead( sRegKey & “\IDDeleted”)

‘ to be sure values is only deleted once, test on marker
If sIDDeleted <> “yes” Then

‘ delete any WinHttpSettings registry entry (interferes with WSUS)
oshell.RegDelete pRegKey & “\WinHttpSettings”

‘ delete values
oShell.RegDelete sRegKey & “\AccountDomainSid”
oShell.RegDelete sRegKey & “\PingID”
oShell.RegDelete sRegKey & “\SusClientId”

‘ Stop and start the Automatic updates service
oShell.Run “%SystemRoot%\system32\net.exe stop wuauserv”, 0, True
oShell.Run “%SystemRoot%\system32\net.exe start wuauserv”, 0, True

‘ Run wuauclt.exe with resetauthorization
sCmd = “%SystemRoot%\system32\wuauclt.exe /resetauthorization /detectnow”
oShell.Run sCmd, 0, True

‘ create marker
oShell.RegWrite sRegKey & “\IDDeleted”, “yes”

End If

Note: this should be copied and saved as a .vbs file. I’ve also attached it as a file to this post, needs to be renamed though!

Reset WSUS Client Script

Enable Jumbo Frames on Hardware ISCSI HBA vmhba

January 30th, 2010

If you need to use jumbo frames on your ISCSI you need to run this command from the command line of the ESX host:

esxcfg-hwiscsi -j enable <vmhbaX>

e.g.

esxcfg-hwiscsi -j enable vmhba1

You’ll need to reboot to let the changes take effect. To verify run:
esxcfg-hwiscsi -l – lists the current settings.

Useful link: http://www.vi-tips.com/2009/04/configuration-of-iscsi-in-vmware-vi3.html

Finding email addresses on an object in Active Directory

August 24th, 2009

http://www.msexchange.org/articles/Finding-Duplicate-SMTP-Addresses.html

Shows how to find an email address within the Exchange infrastructure.

Migrating a DHCP server from one server to another

July 29th, 2009

Heres a neat trick, seems to work ok. Remember however, when you export it switches off the old dhcp server. So be quick!

http://support.microsoft.com/kb/325473/

Nagios – Example using check_icmp

July 24th, 2009

This is what would be needed in your hosts configuration to monitor using check_icmp rather than check_ping.

define service{
use                     generic-service ; Inherit values from a template
host_name               SWITCH    ; The name of the host the service is associated with
service_description     PING            ; The service description
check_command           check_icmp!40.0,10%!100.0,40%  ; The command used to monitor the service
normal_check_interval   5               ; Check the service every 5 minutes under normal conditions
retry_check_interval    1               ; Re-check the service every minute until its final/hard state is determined
}

This is what would be needed in the commands.cfg

# ‘check-host-alive’ command definition
define command{
command_name    check_icmp
command_line    $USER1$/check_icmp -H $HOSTADDRESS$ -w $ARG1$ -c $ARG2$ -p 2
}

This makes the assumption its going to do two pings, otherwise turn “-p 2″ into $ARG3$ instead!

Vi Find and Replace Example

July 24th, 2009

Here is an example of find and replace with VI, this will replace every instance of the “findthistext” string in the file with “replacewithtext”. Neat saves lots of typing!

:%s/findthistext/replacewithtext/g