Reverse DNS lookup with IP Masquerading

Reverse DNS lookup with IP Masquerading

Post by Colin Duroche » Mon, 28 Dec 1998 04:00:00



Hi there,

I just networked the computers in my home and set up ip_masquerading so
that the kids' computers could use my cable modem internet access.  I'm
now wondering if there is a program available (or alternatively, one I
could write) that will allow me to monitor the names of the websites
that are accessed through that connection.  I figure there must be some
way of keeping a list of the external ip addresses that are accessed and
then doing a reverse DNS lookup to find the names.  From there, I could
just scan for certain keywords.

Any help would be very much appreciated,

Colin

 
 
 

Reverse DNS lookup with IP Masquerading

Post by Michael Fu » Mon, 28 Dec 1998 04:00:00



> I just networked the computers in my home and set up ip_masquerading so
> that the kids' computers could use my cable modem internet access.  I'm
> now wondering if there is a program available (or alternatively, one I
> could write) that will allow me to monitor the names of the websites
> that are accessed through that connection.  I figure there must be some
> way of keeping a list of the external ip addresses that are accessed and
> then doing a reverse DNS lookup to find the names.  From there, I could
> just scan for certain keywords.

1. Use packet filters to deny the kids' computers direct access
to the Internet.

2. Set up a proxy (e.g., Squid) on the machine that can still reach
the Internet.

3. Configure the kids' browsers to use the proxy.

4. Spy^H^H^Hmonitor the proxy log files as desired.  With Squid you
could also use ACLs or a redirector to prohibit access to certain
sites.

--
Michael Fuhr
http://www.fuhr.net/~mfuhr/

 
 
 

1. nslookup tries to reverse lookup DNS IP?

I've come across the following phenomenon on a Sun with Solaris 2.6:

when starting nslookup it appears it tries to reverse lookup the DNS's IP.
At least nslookup quits with an error message saying:
XX.XX.XX.XX: cannot find host/domain (or something to that extend)

where XX.XX.XX.XX is the DNS specified in /etc/resolv.conf, which in my
case happens not to have its own DNS entry.

Normal IP resolution works fine, both via /etc/hosts and via DNS (as
configured in /etc/nsswitch.conf),

Can anybody shed some light into that phenomenon?
--
Georg Schwarz    http://home.pages.de/~schwarz/

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