[Cialug] Network slowness
John Lengeling
John.Lengeling at radisys.com
Thu Feb 5 08:59:50 CST 2009
So this IMHO is pointing directly to some issue with the resolver since
it is bypassed when you used the IP address on the ping and you didn't
see a problem.
I would try two things:
1. I would run the system call tracer strace(1) and see if reveals
anything. Run "strace ping IPADDR"
2. The only other thing that could be involved is the name service cache
daemon (nscd). Maybe it is busted or turned off.
If it is off, I would recommend turning it on and then retry your tests.
If it is on, you might try turning it off and see if that affects your
times.
johnl
-----Original Message-----
From: cialug-bounces at cialug.org [mailto:cialug-bounces at cialug.org] On
Behalf Of Tom Sellers
Sent: Thursday, February 05, 2009 8:40 AM
To: Central Iowa Linux Users Group
Subject: RE: [Cialug] Network slowness
I have already done this and the ping response is normal if you ping the
IP address directly. Also if I hook a Windows XP workstation to the
network in the same fashion (directly to the cable modem) it does not
experience this problem. It only affects the linux box.
contents of nsswitch.conf
---------------------------
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference' and `info' packages installed,
try:
# `info libc "Name Service Switch"' for information about this file.
passwd: compat
group: compat
shadow: compat
hosts: files dns
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis
--- On Thu, 2/5/09, John Lengeling <John.Lengeling at radisys.com> wrote:
> From: John Lengeling <John.Lengeling at radisys.com>
> Subject: RE: [Cialug] Network slowness
> To: "Central Iowa Linux Users Group" <cialug at cialug.org>
> Date: Thursday, February 5, 2009, 12:07 AM
> Try pinging the IP address and see if that has the delay.
> If there
> isn't a delay, then your problem is with the DNS
> resolver. If there is
> a delay, then you have some other problem.
>
> What do you have for the host line in /etc/nsswitch.conf?
>
> johnl
>
> -----Original Message-----
> From: cialug-bounces at cialug.org
> [mailto:cialug-bounces at cialug.org] On
> Behalf Of Tom Sellers
> Sent: Wednesday, February 04, 2009 11:40 PM
> To: Central Iowa Linux Users Group
> Subject: Re: [Cialug] Network slowness
>
> This is at home connected directly to my cable modem with
> an ethernet
> cable from the linux laptop.
>
> resolve.conf
> --------------
>
> search globalccs.net
> nameserver 69.63.8.74
> nameserver 69.63.8.73
>
> requested responses
> ---------------------
>
>
> bluto:/home/tsellers# time nslookup www.google.com
> Server: 69.63.8.73
> Address: 69.63.8.73#53
>
> Non-authoritative answer:
> www.google.com canonical name = www.l.google.com.
> Name: www.l.google.com
> Address: 74.125.95.103
> Name: www.l.google.com
> Address: 74.125.95.104
> Name: www.l.google.com
> Address: 74.125.95.147
> Name: www.l.google.com
> Address: 74.125.95.99
>
>
> real 0m1.075s
> user 0m0.008s
> sys 0m0.016s
> bluto:/home/tsellers# time nslookup www.yahoo.com
> Server: 69.63.8.73
> Address: 69.63.8.73#53
>
> Non-authoritative answer:
> www.yahoo.com canonical name = www.yahoo-ht3.akadns.net.
> Name: www.yahoo-ht3.akadns.net
> Address: 209.191.93.52
>
>
> real 0m1.336s
> user 0m0.008s
> sys 0m0.008s
> bluto:/home/tsellers#
>
> A ping to www.yahoo.com takes about 4.5 to 5 seconds to
> respond.
>
>
> --- On Wed, 2/4/09, Jeff Chapin
> <chapinjeff at gmail.com> wrote:
>
> > From: Jeff Chapin <chapinjeff at gmail.com>
> > Subject: Re: [Cialug] Network slowness
> > To: "Central Iowa Linux Users Group"
> <cialug at cialug.org>
> > Date: Wednesday, February 4, 2009, 1:22 PM
> > I am going to maintain that it sounds like a DNS
> issue.
> >
> > What does your /etc/resolv.conf file have in it (at
> both
> > locations)? A
> > listing of the nameservers your windows machine would
> be
> > helpful as well
> > for comparison.
> >
> > Please run the following commands while at home, and
> > provide the
> > answers, as well:
> > # time nslookup www.yahoo.com
> > # time nslookup www.google.com
> >
> > Thanks,
> >
> > Jeff
> >
> >
> > Tom Sellers wrote:
> > > OK I brought my laptop to work today and
> connected it
> > to our vendor only lan that allows only network access
> > outside the plant to the internet etc. (No connection
> to our
> > local network)
> > >
> > > What do you know, the laptop responds much faster
> here
> > and I am connected through a 10 mb hub.
> > >
> > > I guess that either points to my home network or
> my
> > internet provider as the source of this issue. Funny
> that
> > it only seems to affect this linux machine and not my
> > Windows machines.
> > >
> > > Suggestions?
> > >
> > >
> > >
> > >
> > > --- On Tue, 2/3/09, Tom Sellers
> > <tomsellers2001 at yahoo.com> wrote:
> > >
> > >
> > >> From: Tom Sellers
> <tomsellers2001 at yahoo.com>
> > >> Subject: Re: [Cialug] Network slowness
> > >> To: "Central Iowa Linux Users
> Group"
> > <cialug at cialug.org>
> > >> Date: Tuesday, February 3, 2009, 4:57 PM
> > >> No. I have a Motorola Surfboard cable modem
> and a
> > Linksys G
> > >> series wireless router/AP.
> > >>
> > >>
> > >> --- On Tue, 2/3/09, Anthony Jeffries
> > >> <ajeffri at gmail.com> wrote:
> > >>
> > >>
> > >>> From: Anthony Jeffries
> > <ajeffri at gmail.com>
> > >>> Subject: Re: [Cialug] Network slowness
> > >>> To: "Central Iowa Linux Users
> Group"
> > >>>
> > >> <cialug at cialug.org>
> > >>
> > >>> Date: Tuesday, February 3, 2009, 12:56 PM
> > >>> Just out of curiousity, does the OP have
> an
> > Actiontec
> > >>>
> > >> DSL
> > >>
> > >>> modem? I had one
> > >>> of those that insisted on listing itself
> as
> > the first
> > >>> nameserver and it gave
> > >>> my Linux machines a several second delay
> > resolving
> > >>> hostnames.
> > >>>
> > >>> On Tue, Feb 3, 2009 at 12:07 PM, Colin
> Burnett
> > >>> <cmlburnett at gmail.com> wrote:
> > >>>
> > >>>
> > >>>> On Tue, Feb 3, 2009 at 11:33 AM, Tom
> > Sellers
> > >>>>
> > >>> <tomsellers2001 at yahoo.com>
> > >>>
> > >>>> wrote:
> > >>>>
> > >>>>> Aren't the DNS settings
> supplied
> > by
> > >>>>>
> > >> DHCP? If
> > >>
> > >>> I go into
> > >>>
> > >>>> Desktop/Administration/Networking and
> > attempt to
> > >>>>
> > >>> change the DNS settings
> > >>>
> > >>>> they get set back to what they are
> > originally.
> > >>>>
> > >>>> The -R flag to dhcpcd used to prevent
> it
> > from
> > >>>>
> > >> updating
> > >>
> > >>> resolv.conf but
> > >>>
> > >>>> that seems to no longer be there (in
> > 4.0.2, maybe
> > >>>>
> > >> that
> > >>
> > >>> was under 3.x).
> > >>>
> > >>>> Looks like 4.x wants `-C
> resolv.conf` to
> > disable
> > >>>>
> > >>> that.
> > >>>
> > >>>> So, yes, they generally are updated
> by
> > DHCP but
> > >>>>
> > >> you
> > >>
> > >>> can disable that
> > >>>
> > >>>> in some fashion.
> > >>>>
> > >>>>
> > >>>> Colin
> > >>>>
> > _______________________________________________
> > >>>> Cialug mailing list
> > >>>> Cialug at cialug.org
> > >>>>
> http://cialug.org/mailman/listinfo/cialug
> > >>>>
> > >>>>
> > >>>
> > >>> --
> > >>> Tony
> > >>> Mike Myers - "My theory is that all
> of
> > Scottish
> > >>> cuisine is based on a dare."
> > >>>
> > _______________________________________________
> > >>> Cialug mailing list
> > >>> Cialug at cialug.org
> > >>> http://cialug.org/mailman/listinfo/cialug
> > >>>
> > >>
> > >>
> _______________________________________________
> > >> Cialug mailing list
> > >> Cialug at cialug.org
> > >> http://cialug.org/mailman/listinfo/cialug
> > >>
> > >
> > >
> > >
> > > _______________________________________________
> > > Cialug mailing list
> > > Cialug at cialug.org
> > > http://cialug.org/mailman/listinfo/cialug
> > >
> >
> > _______________________________________________
> > Cialug mailing list
> > Cialug at cialug.org
> > http://cialug.org/mailman/listinfo/cialug
>
>
>
> _______________________________________________
> Cialug mailing list
> Cialug at cialug.org
> http://cialug.org/mailman/listinfo/cialug
> _______________________________________________
> Cialug mailing list
> Cialug at cialug.org
> http://cialug.org/mailman/listinfo/cialug
_______________________________________________
Cialug mailing list
Cialug at cialug.org
http://cialug.org/mailman/listinfo/cialug
More information about the Cialug
mailing list