[Cialug] Network slowness
John Lengeling
John.Lengeling at radisys.com
Thu Feb 5 12:23:33 CST 2009
Now if we had the strace from when you were at home, we could compare it
side-by-side and see what is different. So run the strace from home.
I don't know if other distros have different commands, but for
RedHat/Fedora/CentOS, the commands to turn on the name service cache
daemon are:
/sbin/chkconfig nscd on <= so it will start at boot time
/sbin/service nscd start <= to start nscd immediately without a
reboot
/sbin/service nscd restart <= stop/start nscd
/sbin/service ncsd stop <= to stop nscd
Run the chkconfig command above and try the "service nscd restart".
Again you need to perform these tests at home where you see the broken
behavior.
-----Original Message-----
From: cialug-bounces at cialug.org [mailto:cialug-bounces at cialug.org] On
Behalf Of Tom Sellers
Sent: Thursday, February 05, 2009 12:07 PM
To: Central Iowa Linux Users Group
Subject: RE: [Cialug] Network slowness
I have attached the result of the command you suggested but I must tell
you that it doesn't mean anything to me. What should I be looking for?
This one is from my work location so it may not show anything since it
seems to work normally here.
Also where do I look for the Daemon you memtion below. I looked in the
services tab but did not see it there.
Remember I have only been doing this with linux for a couple of months
or so.
--- 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, 8:59 AM
> 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
> > > >>
> > > >
> > > >
> > > >
> > > >
> _______________________________________________
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> > > > http://cialug.org/mailman/listinfo/cialug
> > > >
> > >
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> >
> >
> >
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