DAST: Iperf - bug in virtualk device handling - jschwender --at-- de.ferrotec.com

[Mitch K. <mi...@nc...>]

>Date: Fri, 15 Jul 2005 02:55:11 -0500
>To: jsc...@de...
>Subject: DAST: Iperf - bug in virtualk device handling - jschwender --at--
de.ferrotec.com
>
>
>Contacting DAST re: Bug report about Iperf
>From: Joachim Schwender <jschwender --at-- de.ferrotec.com>
>
>Subject: bug in virtualk device handling
>
>Question/Comment:
>I found a reproducable behavior that i would consider a bug in iperf.
>
>Run iperf (2.0.2) on a server with
>iperf -u -i 1
>the server has a virtual interface configured like eth0:1
>
>run a test from another machine against this virtual device and you find
that not a single
> udp packed reaches the iperf process and therefore is not answered by the
server:
>----X--------------
>
>ots-2:~# iperf -u -c 10.49.1.21
>------------------------------------------------------------
>Client connecting to 10.49.1.21, UDP port 5001
>Sending 1470 byte datagrams
>UDP buffer size:   256 KByte (default)
>------------------------------------------------------------
>[  5] local 10.49.1.22 port 33476 connected with 10.49.1.21 port 5001
>[  5]  0.0-10.0 sec  1.25 MBytes  1.05 Mbits/sec
>[  5] Sent 893 datagrams
>[  5] WARNING: did not receive ack of last datagram after 10 tries.
>ots-2:~#
>----X--------------
>I have traced that back and forth, because i thought u could use iperf to
track a nfs
>problem on one of my machines here, but now i know that iperf is unusable
on virtual
>devices. I tried on 5 different machines:
>redhat 7.3 with kernels from 2.4.27 to 2.4.31, glibc 2.2.5
>debian woody with kernel 2.4.31
>debian sarge with original kernel
>debian sarge with vanilla kernel 2.4.31
>
>testing back and forth shows reproducable that the issue is not related to
glibc, kernel
>or compiler. tcpdump shows that udp packets are going only in one
direction, and the iperf
>thread seems not to react.
>
>btw. the mail address specified in docs does not work:
>----X--------------
>delete your own text from the message returned below.
>
>            The Postfix program
>
><da...@nl...>: host nlanr.net[198.202.123.39] said: 550 5.1.1
>    <da...@nl...>... User unknown
>----X--------------
>
>
>
>
>best regards
>
>
>
--
Mitch Kutzko | mi...@da... | mi...@nc... | 217-333-1199
http://hobbes.ncsa.uiuc.edu/