[CentOS] network hang [was: Re: yum update -> [Errno 4] Socket Error: timed out - More info]

[ken]

On 06/30/2011 11:57 AM Ljubomir Ljubojevic wrote:
> ken wrote:
>> # wget
>> http://ftp.linux.ncsu.edu/pub/CentOS/5.6/updates/i386/RPMS/glibc-common-2.5-58.el5_6.4.i386.rpm
>> --2011-06-30 11:35:44--
>> http://ftp.linux.ncsu.edu/pub/CentOS/5.6/updates/i386/RPMS/glibc-common-2.5-58.el5_6.4.i386.rpm
>> Resolving ftp.linux.ncsu.edu... 152.1.2.172
>> Connecting to ftp.linux.ncsu.edu|152.1.2.172|:80... connected.
>> HTTP request sent, awaiting response... 200 OK
>> Length: 17244521 (16M) [application/octet-stream]
>> Saving to: `glibc-common-2.5-58.el5_6.4.i386.rpm'
>>
>>  5% [=>                         ] 1,029,216   --.-K/s  eta 23m 10s
>> -------------------------------------------------------
>>
>> and just freeze there... except the right two numbers (following "eta")
>> will continue to climb higher... it stays at "5%" and "1,029,216"
>> doesn't change, and there's no activity between those two numbers.  In
>> short, the download just stops or freezes.
>>
> 
> Have you checked your network interface on your network connection in 
> general? First try the same PC in different network environment (home, 
> another location?) and then try to setup another PC with the same IP in 
> the same network environment as original PC.
> 
> Ljubomir
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> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos


In the last half hour I successfully used yum to download and install
strace, krb5-workstation and krb5-libs... for this and other reasons I'm
pretty sure I don't have a network problem.  yum and wget and ftp all
seem to have a problem  downloading
glibc-common-2.5-58.el5_6.4.i386.rpm... perhaps because it's rather
large (16M), or simply larger than 1M.  But then I was able to ftp one
file which was 5M.

Ljubomir, you are correct in that it's some kind of network problem--
well, it could have something to do with limits or some extra-weird
permissions thing I don't know about.  You'll see I've amended the
Subject line to indicate it's probably a network problem.


So, shifting into work-around mode... I used wget to download
glibc-common (the troublesome file) to another machine.  No problem.
Then I scp'd it to the problem machine-- again no problem-- and
successfully installed it there using rpm.


Now that everything's been upgraded, the urgency has gone out of the
situation.  I had thought to use strace and/or tcpdump as was suggested
(thanks for those suggestions), but I've found those utilities give a
lot of output and take a lot of time to analyze (for me anyway).  With
other things I need to get to today, I'll be saving those small projects
for another day.

But just one other quick test: I used scp on the problem box to download
that same glibc-common rpm file from the local machine (residing on the
same LAN and in the same network block) mentioned above.  It worked
fine, even downloading to the same directory (/tmp).  And, yes, rpm
verified that the file was complete and uncorrupted.  This narrows the
problem down to a couple pockets.

If I find anything more, I'll post back.


Thanks for all the suggestions, everyone.

-- 
"When a society comes together and makes decisions in harmony,
when it respects its most noble traditions, cares for its most
vulnerable members, treats its forests and lands with respect,
then it will prosper and not decline."
	--Buddha, Mahaparinirvana Sutra