Red Hat Bugzilla – Bug 20989
rcp and similar commands hang after a short time
Last modified: 2007-04-18 12:29:53 EDT
When using rsync and similar commands that attempt to transfer files, after
a short time a file
transfer hangs. It essentially makes networking useless.
You should try to log this with tcpdump to see what's causing this.
This might also be a classic case of filtering ICMP destination unreachable:
fragmentation needed but don't fragment bit set messages. Is there filtering
done on ICMP between the endpoints?
Created attachment 5730 [details]
The output of tcpdump during problem occurrence
I started tcpdump before issuing a command that hung and stopped it several
minutes later. I have attatched the output to this bug report. If I leave the
command run for a very long time (tens of minutes) more of the file gets
transferred, but at a rate of probably less that 2kb/s. My ethernet is 100MB/s
(a Toshiba 470CDT with a 3COM 10/100 PCMCIA card and a gateway 600 with a 3COM
10/100 PCI card connected via a crossover cable - it has worked for some time
with both machines running RedHat 5.2 then 6.1 then 6.2 but has failed ever
since I upgraded the Gateway to 7.0 - I updated the notebook first and it ran
I believe that I have not altered the standard installation with regard
networking (other than the IP address and /etc/hosts to add some extra hosts).
So I don't believe I have filtering on but how do I tell?
The amount of information that gets transferred before it slows down varies
considerably. Somtimes just a few KB other times not till after tens of MB.
This looks pretty much like a classic half/full duplex problem. The symptom of
it is that tranfers start going fast for about 0.5-2.0 seconds or so, and then
essentially time or are reduced to 0.5-30 Kbytes/sec like with you.
If this is the problem, this should also happen with other protocols, like ftp.
You might want to check your Gateway system's interface configurations
(/etc/modules.conf). Did the driver change at upgrade? Also, try to diagnose
the problem with mii-diag and friends, available from
I got the diag programs from the above web site. The output of vortex.diag
shows the MAC settings of the notebook to be running full-duplex and the gateway
to half-duplex. So it seems the above comment is correct. But how do I change
See /etc/modules.conf for options= line. If there is no such line, the card is
state (if not forced otherwise in EEPROM with NIC DOS configuration floppy).
options 3c59x options=4 full_duplex=1
forces the card to 100/FD. This varies from driver to driver.
I added the line you suggested to /etc/modules.conf and things now work