Full Disclosure mailing list archives
FW: Question for DNS pros
From: "Suzi and Harold VanPatten" <vanpattens () knology net>
Date: Sat, 24 Jul 2004 10:16:26 -0500
It seems to me you could do this without setting up a dns server. Just tcpdump the traffic or sniff or snoop the traffic. It you set it up with a snaplength of 1500 you'll get enough of the packet to see exactly what dns query is being asked...something like tcpdump -n -s 1500 udp and port 53 and host 1.2.3.4 then you'll be able to tell if the queries are all for one specific domain (meaning something has that IP registered as an authoritative server for that domain) or are the queries for many different domains meaning people think you have a dns server they can use as a resolver. We have seen the second case happen before, but generally it has been easy to fix. For instance, if our domain was 192.168.13.0, we'll notice that the source addresses of ALL the queries will come from something like 192.163.13.0 and obviously they have accidentally typo'd something in their dhcp server. Then we use ARIN or some other website to figure out a POC for that network, call them and they fix the typo. Same with issue number one, once you know the domain they are querying, you can find the POC of that domain and get them to fix the problem. Hopefully, it is one of these two issues. Good luck! Suzi Paul Schmehl <pauls () utdallas edu> writes:
What I want to know is *why* do these "foreign" hosts think an IP on my network is serving DNS when there's not even a host at that address. I can think of two possibilities: 1) At some time in the past, a host *was* serving DNS at that address and some "foreign" hosts have cached the address. 2) Someone somewhere has registered a domain and used our IP address for one of their "nameservers" in the registration. (If anyone can think of other explanations, please let me know.)
Some bogus resolver, or forwarder, setup.
Now how is a reverse lookup going to help you with that?
It won't.
The best suggestion yet has been to set up a name server at that address with verbose logging. That's probably what I will do next week.
Yes, just put no zone at all and log queries. After a while, you should be able to figure out "why" you receive these queries. Cheers. _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
Current thread:
- Re: Question for DNS pros, (continued)
- Re: Question for DNS pros Paul Schmehl (Jul 23)
- Re: Question for DNS pros ALD, [ Aditya Lalit Deshmukh ] (Jul 23)
- Re: Question for DNS pros Paul Schmehl (Jul 23)
- Re: Question for DNS pros Steve (Jul 25)
- Re: Question for DNS pros Cyril Guibourg (Jul 23)
- Re: Question for DNS pros Nick FitzGerald (Jul 24)
- Re: Question for DNS pros Dave Yingling (Jul 25)
- Re: Question for DNS pros Steffen Schumacher (Jul 25)
- Re: FW: Question for DNS pros Paul Schmehl (Jul 24)
- Re: FW: Question for DNS pros Paul Rolland (Jul 25)
- Re: FW: Question for DNS pros Paul Schmehl (Jul 25)
- Re: FW: Question for DNS pros Frank Knobbe (Jul 25)
- Re: FW: Question for DNS pros Paul Schmehl (Jul 25)
- Re: FW: Question for DNS pros Paul Rolland (Jul 26)
- Re: FW: Question for DNS pros Paul Schmehl (Jul 26)
- Re: FW: Question for DNS pros Paul Rolland (Jul 27)