sshd 4.2p1 LocalForward interface binding

Alexei Potashnik aleksey at hotmail.com
Wed Nov 30 12:18:54 EST 2005


There seems to be a change in the logic that sshd
uses in selecting interface to bind for LocalForward
requests from the client.

I have the following setup:

ssh client (10.0.0.1) configured with
"LocalForward 1080 127.0.0.1:1080"
is connecting to sshd server (192.168.0.1).

Before installing openssh-4.2p1 sshd would successfully
establish a forwarding connection for the client:
127.0.0.1:xxx -> 127.0.0.1:1080

After installing 4.2p1, sshd still attempts to establish the
connection, but from whatever interface client connected to,
so now connection looks like this:
192.168.0.1:xxx -> 127.0.0.1:1080

Is this a bug or a feature? If this is a feature, is there a way
to control this binding logic? GatewayPorts setting on sshd
doesn't seem to make any difference (I guess it only affects
RemoteForward commands).

Lack of this control becomes a headache, when 192.168.0.1
address is DHCP assigned and you try to enforce policy
of connections from localhost only for sockd server running
on 127.0.0.1:1080...

Thank you
Alexei





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