From mboxrd@z Thu Jan  1 00:00:00 1970
From: Martijn Lievaart <m@rtij.nl>
Subject: Re: DHCP & remote ssh logins
Date: Sun, 29 Apr 2007 17:10:28 +0200
Message-ID: <4634B564.5090702@rtij.nl>
References: <1177853638.11131.46.camel@prix.pricom.com.au>
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To: phil@pricom.com.au
Cc: netfilter@lists.netfilter.org

Phil Rhoades wrote:
> People,
>
> If iptables are setup to only accept ssh logins from particular IPs, how
> do people login when they are on the move and have a DHCP allocated IP?
>   

Ssh to a known box with a fixed IP address and ssh to the target from there.

> I thought I could do this by sending a mail (from the remote DHCP IP)
> formatted in a particular way, to a particular user on the destination
> server which would then be processed, which would then cause a change to
> the iptables setup.  However, I assume other people have had to solve
> this problem and I don't want to re-invent wheels . .
>   

Google for port knocking.

HTH,
M4