On Sat, 2007-05-12 at 14:27 +0100, Karl E. Jorgensen wrote: > On Thu, May 10, 2007 at 09:41:59AM -0500, Dallas Clement wrote: > > I'm getting terrible DNS lookup performance on my Debian Etch system. > > I've installed the "Etch" - Official Beta amd64 version. > > > > After installing, I noticed that the Internet browsers were taking a > > really long time to pull up a web page. I also observed that the > > browser delays seemed to be DNS related as they were spending a lot of > > time "Looking up whatever.com...". > > > > I turned off IPv6 and it made no observable difference. > > How? > > > It seems that a DNS lookup is taking 10s on average. Here is the dig > > output for one such lookup: > > > > debian:/# time dig 192.168.0.1 www.yahoo.com > > ;; Got answer: > [snip] > > ;; Query time: 10 msec > > ;; SERVER: 192.168.0.1#53(192.168.0.1) > > ;; WHEN: Thu May 10 09:39:21 2007 > > ;; MSG SIZE rcvd: 104 > > > > > > ; <<>> DiG 9.3.4 <<>> 192.168.0.1 www.yahoo.com > > ;; global options: printcmd > > ;; Got answer: > [snip] > > ;; Query time: 10 msec > > ;; SERVER: 192.168.0.1#53(192.168.0.1) > > ;; WHEN: Thu May 10 09:39:26 2007 > > ;; MSG SIZE rcvd: 368 > > > > > > real 0m10.031s > > user 0m0.000s > > sys 0m0.000s > > Weird - the elapsed time for the DNS queries are reported as 10 msec > each, yet they are 5 seconds apart? > > > This very same machine also has Windows Vista Ultimate 64 installed on > > it and DNS lookups are lightning fast. There is definitely something > > going on with Debian Etch or perhaps the network configuration. > > Does the other OS use the same DNS server(s)? > > The contents of /etc/resolv.conf might provide clues - especially if > compared to the Windows equivalent (of which I know nothing...) > > > I am using the ndiswrapper around a Windows driver for my Broadcom > > wireless network adapter. > > Shouldn't matter, assuming that you don't have any other network > problems... > >
This is what's in my /etc/resolv.conf: [EMAIL PROTECTED]:~$ cat /etc/resolv.conf search clements nameserver 192.168.0.1 'clements is the name of the local domain. And that is the correct name server on the local domain which happens to be a D-link router. It uses DNS relay to forward DNS requests to my ISP. Interestingly, if I repeat the dig test directly on my ISP DNS server address, the time between queries is dramatically reduced: ---------------------------------------------------------- debian:/home/dallas# time dig 151.164.20.201 debian.org ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 59962 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;151.164.20.201. IN A ;; AUTHORITY SECTION: . 10667 IN SOA A.ROOT-SERVERS.NET. NSTLD.VERISIGN-GRS.COM. 2007051101 1800 900 604800 86400 ;; Query time: 9 msec ;; SERVER: 151.164.20.201#53(151.164.20.201) ;; WHEN: Sat May 12 08:55:23 2007 ;; MSG SIZE rcvd: 107 ; <<>> DiG 9.3.4 <<>> 151.164.20.201 debian.org ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42634 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 0 ;; QUESTION SECTION: ;debian.org. IN A ;; ANSWER SECTION: debian.org. 3600 IN A 192.25.206.10 ;; AUTHORITY SECTION: debian.org. 2615 IN NS rietz.debian.org. debian.org. 2615 IN NS klecker.debian.org. debian.org. 2615 IN NS raff.debian.org. ;; Query time: 138 msec ;; SERVER: 151.164.20.201#53(151.164.20.201) ;; WHEN: Sat May 12 08:55:24 2007 ;; MSG SIZE rcvd: 105 real 0m0.157s user 0m0.004s sys 0m0.000s ---------------------------------------------------------- WOW! And if I directly edit the /etc/resolv.conf and put in the DNS server address of my ISP instead of my relaying D-Link router, lo and behold, my web-browsing is incredibly fast!!! I think we can safely conclude that the problem lies with my router and slow DNS relay. Though I must say that I am a bit mystified as to why Windows is so fast if it presumably relies on the D-link router for DNS relay also. I wish there was a way to keep my ISP DNS addresses in the /etc/resolv.conf file permanently. I think they get overwritten after getting a DHCP response. Thanks for the help. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
