VPN Tunnel Intermittent Connectivity Issue

[Darren Sasso]

Hi All.

We have just setup a IPSEC tunnel between 2 locations.  The tunnel itself is up and stable but i'm having issues when trying to connect to certain webpages at the other end of the tunnel.  It seems as though i need to ping these devices or servers prior to accessing them to wake them up.  When i ping across the tunnel i always loose the first ping.  I believe it may have something to do with ARP and i found a document that said to disable proxy arp on the outside interface which i have done but i'm still having intermittent issues.  Any help would be greatly appreciated.

Thanks in Advance.

[Federico Coto Fajardo]

Hi,

Have you tried adjusting the TCP MSS on the local interface and lowering the MTU size?

If the problem also affects regular PING packets, I would think there's a connectivity problem between the sites.

The tunnel never goes down when this happens?

Federico.

[Darren Sasso]

No i haven't trying adjusting the tcp mss values. I agree i originally thought it was a connectivity issue but the tunnel never drops it's been up for over 10 days.  I'm not sure why the tcp mss values would affect ping though.

Thanks.

[Federico Coto Fajardo]

The TCP MSS will not affect PING packets (only TCP traffic).

Are you getting any messages on the logs or any errors at all that might help?

Federico.

[Darren Sasso]

No errors yet but i'm still looking.  Thanks.