openssh unix dev - Aug 2004 - OOB packets and port forwarding

I have an application that uses a 1-byte OOB packet
for a heartbeat signal. It appears that openssh blocks
these packets when I use it to forward to a remote
port.
The application works fine when connected to the
server
using the port forward, but all heartbeat packets are
stripped out from the socket data.

Is this intentional? Is it a bug? I've tried several
versions of openssh without success.

Any hints or help will be very appreciated.

Thanks,
George


		
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George Faber wrote:
> I have an application that uses a 1-byte OOB packet
> for a heartbeat signal. It appears that openssh blocks
> these packets when I use it to forward to a remote
> port.
> The application works fine when connected to the
> server
> using the port forward, but all heartbeat packets are
> stripped out from the socket data.
> 
> Is this intentional? Is it a bug? I've tried several
> versions of openssh without success.
> 
> Any hints or help will be very appreciated.
By OOB data, I presume you mean TCP segments with URG flag set?

The SSH protocol does not have the means to preserve these across
a port forwarding. It may be possible to add, but it would require a
protocol extension, perhaps using SSH_MSG_CHANNEL_EXTENDED_DATA.

-d