VTP Problem...I think

[Jmiller278]

We have 3 2900 switches (L2) and 2 3550 (L3) switches. Configured on all of them are 15 vlans. To pass DHCP from a single server we have put IP addresses on the vlans. config looks as such

Switch1>vlan1 ip address 192.168.1.1
Switch2>vlan1 ip address 192.168.1.1
Switch3>vlan1 ip address 192.168.1.1
Switch4>vlan1 ip address 192.168.1.1
Switch5>vlan1 ip address 192.168.1.1
Switch6>vlan1 ip address 192.168.1.1

You get the idea....

So you can see that in each net there is excessive ARP brodcasts from the duplicate IPs. In the past we set VTP MODE to transparent and the broadcasts stopped. Unfortunately they are back again and im not sure what the deal is. Ive disabled and re-enabled the VTP commands and no dice. Ive left out alot of info but Im confident this is an easy fix. The layer 2 devices do not arp, just the 2 L3 ones fighting back and forth. Any help is much appreciated. THANKS!!!

 

[robertjo24]

If I read this correctly, you set the management IP address of each switch the same?

Each switch should have a differnt IP address assigned,all on the same magement VLAN.
All switches should have the same VTP domain set.

Ensure the trunking protocol is set correctly between the switches. The 2900's default to ISL, I am not sure what the 3550's default to.

 

[vipergg]

Ok , the ip address on your 2900's is to manage the switch only , has nothing to do with routing . Basically if you want to route between vlans you would set up trunking between the 3550's and the 2900's . All your layer 3 routing setup is done at the 3550. For each layer 3 SVI on the 3550 you would add the following command " ip helper-adress XXX.XXX.XXX.XXX. Where XXX is the address of your dhcp server , you would not need the command on the subnet that the dhcp server is actually on. And no you cannot have the same address on all your switches , decide which subnet you want to manage the switches in and give each switch a different address within that subnet.