Networking Forums

Networking Forums > Computer Networking > Linux Networking > strange delay while dns resolve

Reply
Thread Tools Display Modes

strange delay while dns resolve

 
 
Kevin =?ISO-8859-15?Q?B=F6rgens?=
Guest
Posts: n/a

 
      01-27-2005, 04:21 PM
Hi

I experience a problem I don't understand - in fact, I have no clue what
could create it.

I have a Debian notebook being connected to a router which is connected to
the german dsl net.

If I ping my router or a ip out in the internet, everything is fine:

-----------8<------------
64 bytes from 64.233.167.99: icmp_seq=15 ttl=244 time=147 ms
64 bytes from 64.233.167.99: icmp_seq=16 ttl=244 time=148 ms
64 bytes from 64.233.167.99: icmp_seq=17 ttl=244 time=148 ms
64 bytes from 64.233.167.99: icmp_seq=18 ttl=244 time=147 ms
64 bytes from 64.233.167.99: icmp_seq=19 ttl=244 time=148 ms
64 bytes from 64.233.167.99: icmp_seq=20 ttl=244 time=148 ms
64 bytes from 64.233.167.99: icmp_seq=21 ttl=244 time=146 ms
64 bytes from 64.233.167.99: icmp_seq=22 ttl=244 time=147 ms

64 bytes from 192.168.0.1: icmp_seq=5 ttl=255 time=1.03 ms
64 bytes from 192.168.0.1: icmp_seq=6 ttl=255 time=0.979 ms
64 bytes from 192.168.0.1: icmp_seq=7 ttl=255 time=0.985 ms
64 bytes from 192.168.0.1: icmp_seq=8 ttl=255 time=0.990 ms
64 bytes from 192.168.0.1: icmp_seq=9 ttl=255 time=1.02 ms
64 bytes from 192.168.0.1: icmp_seq=10 ttl=255 time=0.993 ms
64 bytes from 192.168.0.1: icmp_seq=11 ttl=255 time=0.970 ms
64 bytes from 192.168.0.1: icmp_seq=12 ttl=255 time=0.994 ms
-------------->8--------------

as you can see, I didn't use the dns server but pinged using the ip.
When I ping using the host name instead, something strange happens:
The ping times stay the same but between each ping is a 2 second delay, I
think it is the time where the host name is resolved to its ip.
resolveip <host name> has the same delay

I experience the same delay when I do a "route"

------------------8<-------------
Kernel IP Routentabelle
Ziel Router Genmask Flags Metric Ref Use
Iface
localnet * 255.255.255.0 U 0 0 0 eth0
###2 seconds delay###
default SE515.home 0.0.0.0 UG 0 0 0 eth0
----------------->8---------------------

Its clearly a problem of my machine because the other clients in this net
don't have it but I still have it if I use a friend's net. I don't think
its a hardware problem either, because using wlan it was the same.

Any help appreciated,
Kevin

 
Reply With Quote
 
 
 
 
Andrew Schulman
Guest
Posts: n/a

 
      01-27-2005, 06:44 PM
> Hi
>
> I experience a problem I don't understand - in fact, I have no clue what
> could create it.
>
> I have a Debian notebook being connected to a router which is connected to
> the german dsl net.
>
> If I ping my router or a ip out in the internet, everything is fine:
>
> -----------8<------------
> 64 bytes from 64.233.167.99: icmp_seq=15 ttl=244 time=147 ms
> 64 bytes from 64.233.167.99: icmp_seq=16 ttl=244 time=148 ms
> 64 bytes from 64.233.167.99: icmp_seq=17 ttl=244 time=148 ms
> 64 bytes from 64.233.167.99: icmp_seq=18 ttl=244 time=147 ms
> 64 bytes from 64.233.167.99: icmp_seq=19 ttl=244 time=148 ms
> 64 bytes from 64.233.167.99: icmp_seq=20 ttl=244 time=148 ms
> 64 bytes from 64.233.167.99: icmp_seq=21 ttl=244 time=146 ms
> 64 bytes from 64.233.167.99: icmp_seq=22 ttl=244 time=147 ms
>
> 64 bytes from 192.168.0.1: icmp_seq=5 ttl=255 time=1.03 ms
> 64 bytes from 192.168.0.1: icmp_seq=6 ttl=255 time=0.979 ms
> 64 bytes from 192.168.0.1: icmp_seq=7 ttl=255 time=0.985 ms
> 64 bytes from 192.168.0.1: icmp_seq=8 ttl=255 time=0.990 ms
> 64 bytes from 192.168.0.1: icmp_seq=9 ttl=255 time=1.02 ms
> 64 bytes from 192.168.0.1: icmp_seq=10 ttl=255 time=0.993 ms
> 64 bytes from 192.168.0.1: icmp_seq=11 ttl=255 time=0.970 ms
> 64 bytes from 192.168.0.1: icmp_seq=12 ttl=255 time=0.994 ms
> -------------->8--------------
>
> as you can see, I didn't use the dns server but pinged using the ip.
> When I ping using the host name instead, something strange happens:
> The ping times stay the same but between each ping is a 2 second delay, I
> think it is the time where the host name is resolved to its ip.
> resolveip <host name> has the same delay
>
> I experience the same delay when I do a "route"
>
> ------------------8<-------------
> Kernel IP Routentabelle
> Ziel Router Genmask Flags Metric Ref Use
> Iface
> localnet * 255.255.255.0 U 0 0 0 eth0
> ###2 seconds delay###
> default SE515.home 0.0.0.0 UG 0 0 0 eth0
> ----------------->8---------------------


Right, and probably route -n doesn't give you that same delay, because
the delay is in DNS resolution.

You say this is happening on your host but not elsewhere on your LAN.
That's good, because it means it's just a local configuration problem;
the upstream DNS servers are responding properly.

The obvious reason that DNS resolution would be slow is that your host
is configured to query a DNS server first that's not answering. So you
have to wait before going on to a server that does answer. What are the
contents of /etc/resolv.conf? Are all of the nameservers mentioned
there functioning?

--
To reply by email, replace "deadspam.com" by "alumni.utexas.net"
 
Reply With Quote
 
Kevin =?ISO-8859-15?Q?B=F6rgens?=
Guest
Posts: n/a

 
      01-27-2005, 08:04 PM
Hi

> The obvious reason that DNS resolution would be slow is that your host
> is configured to query a DNS server first that's not answering. So you
> have to wait before going on to a server that does answer. What are the
> contents of /etc/resolv.conf? Are all of the nameservers mentioned
> there functioning?


Oh no, you are right. The first dns server seemes to be offline.

Thank you for your quick help,
Kevin
 
Reply With Quote
 
 
 
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
IE 6 cannot resolve DNS attomsriver@yahoo.com Windows Networking 1 12-22-2006 01:57 AM
Resolve DNS DerekP Wireless Networks 0 04-11-2006 08:56 PM
can't resolve DNS lou Broadband Hardware 2 10-18-2004 03:44 AM
Strange Problem with my Base Station MN500 (MS Support was not able to resolve) Amar Broadband Hardware 3 01-31-2004 01:20 AM
DNS Resolve Charles A. Lackman Windows Networking 0 08-25-2003 04:49 PM



1 2 3 4 5 6 7 8 9 10 11