Corrupted MAC on input

[Georgi Georgiev]

I hope the experience I had with this problem could shed some light to the more
knowledgable.

I started having the "Corrupted MAC on input" since a few days ago. I do not
know what the cause is, but from what I've read in this thread, it could be an
ssh problem.

I have not changed the configuration on my machine in any way. The only machine
I have a problem with is a

$ uname -a
IRIX64 onyx 6.5 10151453 IP35
http://onyx.hucc.hokudai.ac.jp/cgi-bin/MachineInfo

The computer I connect from is a Gentoo Linux, Single P4 3.0GHz HT, running SMP
vanilla kenrel 2.6.6. The ssh client identifies itself as
SSH-2.0-OpenSSH_3.8p1.

The server side, I do not have much control over. The ssh daemon presents the
following greeting: SSH-1.99-OpenSSH_3.6.1p2

I get these Corrupted MAC errors very, very often now (I had never seen one
until a few days ago). The easiest way to cause them is to start vi and start
going up and down in a text file.

These errors occur with SSHv2 conections only. If I connect with ssh -1 there
is no problem, regardless if I turn on compression to level 9.

After reading the comment about a possible problem with compression, I tried
running "find /" to see if this will cause a Corrupted MAC, but it worked fine.
I seem to have problems only when at input (never on output). The error always
interrupts me in the middle of whatever it is I am typing. Speed doesn't seem
to be an issue.

I copied a 11MB file using scp *from* that server, without a problem:
$ scp onyx:mpich.tar.gz dump
However, copying the same file *to* the server fails almost immediately:
$ scp dump onyx:

I also captured a complete ssh session using tcpdump. Replaying it with tcpdump
-r shows only 74 frames (the dumped file is 7249 bytes). I could post it if
anyone thinks it can help.

I captured the failing scp session as well. The quicker of the two captures
contains only 30 frames.

I would like to know your opinion about what the cause of the problem is.

Please make sure you CC: any replies as I am not a subscriber.

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