Problems connecting to a single host after changing 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 Site

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.

I'm missing out on something after the change. Strange that it only happens on this particular host. Hope you guys could advise me.

Thanks, latour

Reply to
latouring
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Misconfigured IP gateway on host with problem ???

Is proxy ARP enabled on current router ?

Is proxy ARP disabled on new router ?

I
Reply to
Merv

Misconfigured IP gateway on host with problem ???

Is proxy ARP enabled on current router ?

Is proxy ARP disabled on new router ?

I
Reply to
Merv

Hi Merv,

Thanks for the reply.

  1. Gateway is configured correctly
  2. Proxy ARP disabled
  3. Proxy ARP disabled.

Proxy ARP is enabled on the FWSM.

Thanks!

Reply to
latouring

Might I suggest creating an simple access-list with the offending host's IP address and running a 'debug ip packet detail' to see what's happening to the packets on the 6509? This should be able to tell you if you if it's being routed incorrectly for some reason. Also, do you have any sort of policy routing enabled? That could possibly create issues.

Thanks, Phillip

snipped-for-privacy@gmail.com wrote:

Reply to
pcmccollum

Another troubleshooting step would be to run traceroutes in both directions, and see how far each one gets.

Reply to
Barry Margolin

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