OT: Getting local IP addresses from a gateway

[Tim]

On Sun, 2012-04-22 at 15:09 -0700, Jonathan Ryshpan wrote:
> I need to get the IP numbers of local hosts, i.e. hosts inside my
> gateway's firewall.  The domain name server in the gateway provides
> the IP addresses of hosts and sites on the internet, but does not
> provide the IP addresses for hosts on my local net.

It's quite common for domestic routers to not bother with reverse name
lookups as well as forward ones (since the average user won't need the
feature, there's little incentive for them to include it).

Long ago, I decided that if I wanted a name resolution on my LAN, that I
should run a local name server on one of the computers, rather than let
a modem/router do a half-assed job.  So I went the whole hog.  I turned
off the DHCP server in the router, and ran one in the server PC, along
with a DNS server on the server that talked to the DHCP server.

Permanent machines get doled out the same IP by the DHCP server, and the
DNS server resolves their addresses in both directions (*).  Visiting
machines get doled out a temporary IP, their addresses are temporarily
entered into the DNS server recorded, and their addresses are resolved
in both directions.  And my DNS, also, resolves all queries about WWW
addresses for the LAN PCs.

I've never regretted doing so.  I appreciate it all the more for being
able to kill some addresses through my name server (any lookups related
to them fails - doubleclick.com doesn't work, at all, now; likewise with
many other annoyances).

* "Both directions" meaning that a forward lookup of asking for the IP
for an name, and a reverse lookup of a name for an IP, both work.

-- 
[tim at localhost ~]$ uname -r
2.6.27.25-78.2.56.fc9.i686

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