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Connectivety Problem after switching router/link

Dear All,

I'm stuck with a problem encountered recently, hope the kind souls here

could give me a clue to the problem.

Currently we have a 64kbps circuit to a remote site and we have plan to

move it to a new circuit (T1) on a new router. I have recently

performed a test on a new circuit (faster) on the new router to the

remote site.

I configured the new router on the T1 having the same internal

interface IP address so that I do not have to change the default

gateway on the clients configured with static addresses. I did the

switch by disconnecting the link on the router connected to the 64kbps.

All went well except only a single host at secured vlan20 and another

host at the remote site have problems connecting to each other.The

affected host on vlan20 has no problems connecting to the other hosts

at the remote site.

The connectivety between the other secured vlans to the hosts at the

remote site is fine.

host on vlan20--FWSM--6509--Checkpoint--1721--{IPVPN}--1721--Remote


I have cleared the arp-cache on the connected routers/switches/hosts

and even reloaded the devices but it didnt help. traceroute from the

remote site stops at the 6509 core switch and I dont see anything

hitting vlan20 from the FWSM logs. I do see outgoing traffic from the

host on vlan20 hitting the access-list created on the FWSM but it didnt

even hit the checkpoint firewall. It looks likes the traffic stops at

the 6509 but there are no access list applied. ARP Proxy is enabled on the FWSM. Once I switched back to the 65kbps circuit, everything was back to normal.

I'm missing out on something after the change. Strange that it only

happens on this particular host. Hope you guys could advise me.




Re: Connectivety Problem after switching router/link


when you say 'secured VLAN', what are you referring to, configuration-wise ? Can you post the configurations of all devices involved, and indicate which IP addresses are not able to connect to each other ?




Re: Connectivety Problem after switching router/link

Do you mean only occured at two hosts, one at VLAN 20 and one at remote site ? If it is only changed the from 64k to T1, it shouldn't be any L3 problem.

How about if the host at remote try to connect to that host at VLAN 20 ? Where is the packet stop ?

Did you checked w/ the IPVPN provider ?

I suggest to clear the cache of 6509 and firewall as well if possible.

Configuration files are required for detail investigation.

Hope this helps.

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