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New Member

SSH Hangs

Running SSHv2 through a hardware vpn tunnel setup on Cisco 3745 Routers (across the Internet to two different sites, 3745s on both ends).

One system works fine, other identical systems (and various different systems - all Win2k or Winxp) will "hang" on the SSH session when it goes to load a large block of text on the screen.

Running WireShark on the failing system's connections, the other boxes show TCP Checksum Incorrect on various packages and when they fail they show "tcp previous segment lost" and "a segment before this frame was lost".

Again, one system running WinXP sp2 (using a Broadcom Gigabit nic) works fine. Every other system on the network hangs at this spot.

The VPN tunnel has the whole subnet included in the VPN tunnel. We've triple checked that the ACLs are identical on both ends.

Basic connectivity is fine, it just fails when it loads the large block of text listing available commands.

A continuous 10kb ping has no packet loss, no timeouts for >100 pings, at 88msec.

TELNET is an available option, it also fails identically, but again, on that one "magic system" TELNET also works fine.

I have exhausted everything I know about SSH, networks, VPN and the like. Though, I will add that other sites on a Point to Point network, sharing the same domain work fine. It is our remote site through the VPN tunnel that fails.

Any ideas are appreciated.

New Member

Re: SSH Hangs

Reduced the MTU to 1300, works fine now.