ssh client auto rekey feature.

[John A Grahor]

I plan to use ssh as the secure transport of a VPN.  (Yes I know there are
other solutions but...)

These tunnels may be up for a long time, days or weeks, and escape
characters will be turned off because I'll be passing binary data so I can't
force a rekey with that method.

Since the ssh spec says one should rekey every hour, I plan to patch the ssh
client to implement an auto-rekey option.

Do any of the security/cipher gurus have any problem with automatically
rekeying the connection at a specific interval.  For simplicity's sake I
just plan to implement a simple timer that goes off every
user-specified-interval and rekeys the connection.

If the developers are interested, I'll send the patch along when I'm done.

Thanks,
John