I've been getting errors such as the following on one of my systems recently...
Jul 29 11:15:33 localhost sshd[26456]: Corrupted MAC on input. Jul 29 11:15:33 localhost sshd[26456]: ssh_dispatch_run_fatal: Connection from 123.123.12.34 port 61436: message authentication code incorrect
These tend to happen during large rsync runs, which causes rsync to abort.
Following some advice I found on The Google, I tried setting various different values for the "MACs" keyword in sshd_config, but it doesn't seem to change the behaviour. (And, yes, I did remember to restart the sshd service after each config change. Running "ssh -vvv" to the host shows that it's negotiating the new MAC protocol.)
What's the likely cause of this? A bad NIC? Bad RAM? (I'm guessing something is corrupting the packets once in a while, but I'm not sure what. If so, it seems to get past TCP's error correcting.)
Has anyone else come across this before, and have a suggestion?
Thanks, Gilbert