Date: Wed, 24 Oct 2007 13:33:27 -0500 From: Eric F Crist <ecrist@secure-computing.net> To: freebsd-questions@FreeBSD.ORG, ecrist@secure-computing.net Subject: Re: reverse DNS resolution... Message-ID: <192D2FDC-31FE-44DB-9883-AA506BCCDCA2@secure-computing.net> In-Reply-To: <200710231700.l9NH0HKu043964@lurza.secnetix.de> References: <200710231700.l9NH0HKu043964@lurza.secnetix.de>
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Thanks to all for their help. I was ignoring the forward DNS, and =20 many things don't resolve reverse DNS unless there's a matching =20 forward DNS. duh. thanks! Eric Crist On Oct 23, 2007, at 12:00 PMOct 23, 2007, Oliver Fromme wrote: > Eric F Crist wrote: >> As I already stated, if I do a host 172.30.x.x, I get a the correct >> reverse resolution. dig works as well. What isn't working is the >> reverse resolution in certain command outputs, etc. > > Note that the DNS tools (host, nslookup, dig) use their > own resolver code, not the one from FreeBSD's libc, like > all other tools. That might explain the difference. > > Make sure that you have configured /etc/nsswitch.conf > and /etc/resolv.conf correctly. Also note that /etc/hosts > overrides DNS by default. > > You can use tcpdump to check if a reverse lookup request > is sent to the DNS server when the failure occurs, and > what the reply looks like. E.g. let this command run in > one terminal: > > # tcpdump -i tun0 -s 1500 -l -n -vvv udp port domain > > Add an -i option to specify the interface to listen on, > if you have multiple interfaces (e.g. -i fxp0). > > Then run the command (w, irc client, whatever) in another > terminal and watch the tcpdump output. Oh by the way, > I think the addresses in IRC are resolved by the servers, > not by the clients, so you would have to run the tcpdump > command on the IRC server (if it's an internal one to > which you can login and have root access). > > Best regards > Oliver > > --=20 > Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing =20 > b. M. > Handelsregister: Registergericht Muenchen, HRA 74606, =20 > Gesch=E4ftsfuehrung: > secnetix Verwaltungsgesellsch. mbH, Handelsregister: =20 > Registergericht M=FCn- > chen, HRB 125758, Gesch=E4ftsf=FChrer: Maik Bachmann, Olaf Erb, Ralf =20= > Gebhart > > FreeBSD-Dienstleistungen, -Produkte und mehr: http://=20 > www.secnetix.de/bsd > > PI: > int f[9814],b,c=3D9814,g,i;long a=3D1e4,d,e,h; > main(){for(;b=3Dc,c-=3D14;i=3Dprintf("%04d",e+d/a),e=3Dd%a) > while(g=3D--b*2)d=3Dh*b+a*(i?f[b]:a/5),h=3Dd/--g,f[b]=3Dd%g;} > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-=20 > unsubscribe@freebsd.org" ----- Eric F Crist Secure Computing Networks
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