Date: Tue, 23 Oct 2007 19:00:17 +0200 (CEST) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-questions@FreeBSD.ORG, ecrist@secure-computing.net Subject: Re: reverse DNS resolution... Message-ID: <200710231700.l9NH0HKu043964@lurza.secnetix.de> In-Reply-To: <5E76A4F8-0C80-412F-BA07-99CFEC08E062@secure-computing.net>
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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 -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M. Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung: secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün- chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd PI: int f[9814],b,c=9814,g,i;long a=1e4,d,e,h; main(){for(;b=c,c-=14;i=printf("%04d",e+d/a),e=d%a) while(g=--b*2)d=h*b+a*(i?f[b]:a/5),h=d/--g,f[b]=d%g;}
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