I was doing some cisco exercises on configuring a vtp server and client, something I can't figure out is :
I setup a vtp server, added my VLAN's
I then took another switch that was attached to this vtp server and
set it to client
Is there a way to push the configs, like a force update command ?
You can't manually force updates because VTP configs are pushed based on the highest current VLAN database revision number. Normally, after every change to your VTP config the configuration revision number should be incremented. The only way to force update this is by actually doing a VTP database change.
If VTP is not updating the VLANs correctly, check to make sure the MD5 digest on all VTP domain switches is the same. The MD5 digest is calculated using the revision number, domain name, and password to make sure the information in the VTP update can be trusted. I've seen issues where switches configured with the same domain and password, but the MD5 digest is not aligned until I update the VLAN database on the VTP server. This is typically caused by the local revision number being different between the switches. Making a VLAN change on the VTP server will send out a VTP update to all domain switches with the newest revision number so that the MD5 digests should align properly.
You can see the VTP md5 digest with a "show vtp status" command on each switch:
SW1(config)#do sh vtp statu
VTP Version : 2
Configuration Revision : 0
Maximum VLANs supported locally : 1005
Number of existing VLANs : 17
VTP Operating Mode : Server
VTP Domain Name : CISCO
VTP Pruning Mode : Enabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x09 0xF0 0xD7 0x82 0xB7 0x08 0x82 0xAA
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
Local updater ID is 155.1.7.7 on interface Vl7 (lowest numbered VLAN interface found)
SW2(config)#do sh vtp statu
VTP Version : 2
Configuration Revision : 0
Maximum VLANs supported locally : 1005
Number of existing VLANs : 17
VTP Operating Mode : Client
VTP Domain Name : CISCO
VTP Pruning Mode : Enabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x09 0xF0 0xD7 0x82 0xB7 0x08 0x82 0xAA
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
Updates to VTP are only sent out when there is an increment to the VTP revision number. The only way to 'force' an update is to create an erroneous Vlan and then delete it. This will accomplish a 'force update' and send the change out to the rest of your clients.
An alternate way to force an update is to change the switch that needs the update to Transparent mode which resets the counter to Zero and then put it back into client mode or server mode. This will force the switch to jump from revision 0 to whatever the current highest revision is and the database will be overwritten.
Hope this helps.
Change the domain of the client and rechange it back to the same domain this should reset the VTP counter and now the client will get the VLANS from the VLAN server
While most people get the vtp config setup they sometimes forget to trunk the interface. When all your vtp stuff looks right (but config rev not incrementing/updating) then it's probably a trunking issue on the int itself - try switchport trunk encap dot1q/isl then switchport mode trunk - should do the trick - kerry_13 had this exactly right, that answer should be at the top for all the times i've seen new guys do it.
I think you should check whether you configure the client switch port with mode trunk or not, it update automatically, right after you put the right domain name and password.
A vtp advertisement is sent only when their is a change in the revision number. How we can change the revision number? Pretty easy.. create and delete a dummy vlan. We cant force a client to pull the update from the server.
