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New Member

vrrp and /30 subnets

Our ISP hands us an ethernet link. ISP router has one address of (for argument sake) 1.1.1.0/30 net, - let's say they have 1.1.1.1 we have the other usable address of 1.1.1.2/30 assigned to our 3825 router. Is it possible to use hsrp or vrrp if there is not two valid/unique "wan" IPs to assign to our routers? For example, if we had a pair of 3825 routers? are we stuck with basically a manual failover or requesting our isp to provide a larger address wan block ?

any feedback appreciated!

someone else had same question at :

http://www.networking-forum.com/viewtopic.php?t=2915

but no real answer given from what I could tell.

2 REPLIES
New Member

Re: vrrp and /30 subnets

Hello

I found a similar question / solution on the following location http://lathiat.livejournal.com/36658.html

New Member

vrrp and /30 subnets

I commented at the above livejournal entry, but I'll post here as well.  You can do this in VRRP by using a secondary address.  I've only tested this in a lab environment, so use at own risk:

Scenario:  ISP has allocated a 192.168.100.0/30 - they have taken 192.168.100.2 and your end is to use the address 192.168.100.1

Setup the two routers as follows...

Router1:

----------------

interface FastEthernet1/0

ip address 192.168.1.1 255.255.255.0

vrrp 1 ip 192.168.1.10

vrrp 1 ip 192.168.100.1 secondary

!

ip route 192.168.100.0 255.255.255.252 FastEthernet1/0

----------------

Router2:

----------------

interface FastEthernet1/0

ip address 192.168.1.2 255.255.255.0

vrrp 1 ip 192.168.1.10

vrrp 1 ip 192.168.100.1 secondary

!

ip route 192.168.100.0 255.255.255.252 FastEthernet1/0

================

It does complain about having the secondary not being in the same subnet, but does work.

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