Out of Order packets

[kbing]

Has anyone experienced receiving Out of Order packets from their ISP and have had traffic going thru VPN tunnel drop?

Scenario: Remote End running Cisco 871 router 12.4 IOS. Head end running PIX 515 v6.3 IOS. I have an IPSec VPN tunnel going between the PIX and router.

Intermittently, the INSPECT process on the Router will drop telnet traffic that is coming back from a system at the head end site. It doesn't always drop the packets...only periodically.

If you have seen this what have you done to fix it. So far we have switched to our secondary ISP...seems were getting less Out of Order packets from them but still getting them.

 

[helpdeskdan]

Packet fragmentation perhaps? You could try changing the MTU.

 

[KiscoKid]

What medium is the VPN tunnel established over? T1, DSL, Internet, something else?

Do you have interleaving enabled on your VPN endpoint?

 

[kbing]

The router is a Cisco 871 with ethernet to our ISP's Cable modem.

 

[UnaBomber]

Not usual, unless your ISP is brown-outing, or your packets are all taking different routes...

You say the telnet session is dropped, but is the tunnel broke?

UnaBomber
ccnp mcse2k

 

[helpdeskdan]

I was thinking load balancing across 2 links at the ISP somewhere - I believe VPN adds 1 bit to the packet, it gets fragmented & the small part gets there first. That's a good point - is the tunnel dropping too?