On Wednesday 02 September 2009, walt wrote:
> On 09/02/2009 07:11 AM, Helmut Jarausch wrote:
> > Hi,
> >
> > I'd like to allow remote access (via ssh only) to a given machine.
> > Unfortunately, my remote IP is dynamic and reverse lookup
> > (e.g. specifying only_from = .skynet.be in /etc/xinetd.conf) doesn't
> > work. So, I have to find out which IP ranges are used by a given
> > internet provider (e.g. skynet.be).
> >
> > Does anybody know how to find out?
>
> Here's a quick and dirty trick:
>
> $host skynet.be
> skynet.be has address 195.238.10.70
>
> $whois -H 195.238.10.70
> <snip>
> % Information related to '195.238.0.0 - 195.238.31.255'
> inetnum:        195.238.0.0 - 195.238.31.255
> netname:        SKYNET-B
> descr:          Belgacom SA/NV
> descr:          Internet access provider
>
> As Paul said, though, asking them is more accurate.

Most ISPs have a web accessible control panel which should indicate which IP 
address you currently have.  Alternatively, you can have your home 
server/router pinging an external server every 15 minutes or so and check the 
incoming logs of the external server for the change of the incoming IP 
address.  The DynDNS solution must be the simplest though.
-- 
Regards,
Mick