Hi,

I'm experiencing a very strange problem while configuring my firewall
on my linux box. I'm connecting to this linux box from my home
computer running windows, using PuTTY. It seems in order to SSH to my
linux box, from another computer, I need an open, UDP port range
somewhere between 42000 to 42200 on my firewall. I tried tracing this
down to a specific port, but it seems whatever this is, it changes
every few minutes.

If this UDP range isn't open, I cannot open a SSH connection to my
linux box.

I'm totally baffled here, ssh has always been available to me with
just port 22. Could this be some type of back door into my system?
(We have had "consultants" work on our server at some times).

I don't see anything in the secure logs about these failures, and I
tried running nmap on my server, and I can't see any open UDP ports in
this range.

Does anyone know what is going on here?

woodswatcher@gmail.com writes:

> Hi,
>
> I'm experiencing a very strange problem while configuring my firewall
> on my linux box. I'm connecting to this linux box from my home
> computer running windows, using PuTTY. It seems in order to SSH to my
> linux box, from another computer, I need an open, UDP port range
> somewhere between 42000 to 42200 on my firewall. I tried tracing this
> down to a specific port, but it seems whatever this is, it changes
> every few minutes.
>
> If this UDP range isn't open, I cannot open a SSH connection to my
> linux box.

Does ssh -vv to the box say anything useful when attempting to auth
without the port range open?

> Does anyone know what is going on here?

Slap wireshark on your box and capture traffice while you're trying to
connect... and it too can give you clues as to what if anything is
going on in that port range.

--
Todd H.
http://www.toddh.net/