Red Hat Bugzilla – Bug 136618
Ethereal reports wrong checksum on outgoing UDP packets
Last modified: 2007-11-30 17:10:52 EST
Description of problem:
When Ethereal captures outgoing UDP packets it reports a wrong
checksum on them however when I use it to capture the packets on the
receiving side the checksum is OK.
Version-Release number of selected component (if applicable):
0.10.5 from current devel
Run a program which sends out UDP packets and capture them using Ethereal.
Steps to Reproduce:
The captured packets have incorrect checksum but in fact they haven't
as verified on receiving side.
The captured packets have correct checksum.
tcpdump seems to capture the packets with right checksum.
Sorry for the last info: tcpdump actually captures the packets with
WRONG checksums too. So the problem lies probably in libpcap?
Created attachment 105578 [details]
A very simple program to send UDP packets
Change IP address to host you want to send the packets to.
02:0c.0 Ethernet controller: Intel Corp. 82540EM Gigabit Ethernet
Controller (rev 02)
Subsystem: Dell Computer Corporation: Unknown device 0151
Flags: bus master, 66Mhz, medium devsel, latency 64, IRQ 9
Memory at fcfe0000 (32-bit, non-prefetchable)
I/O ports at df40 [size=64]
Capabilities: [dc] Power Management version 2
Capabilities: [e4] PCI-X non-bridge device.
Capabilities: [f0] Message Signalled Interrupts: 64bit+
libpcap version 0.8.3, kernel 2.6.8-1.610
some network cards compute the checksum on their own..
maybe a dup of bug #129823
Oh, same NIC...
*** This bug has been marked as a duplicate of 129823 ***
This is described by ethereal developers -
Changed to 'CLOSED' state since 'RESOLVED' has been deprecated.