I have seen such and issue but it depends on the environment structure.
I have seen it mostly on VM's and it was resolved.
The hardware and software details of the setup might help to understand
what's causing it.
Eliezer
----
Eliezer Croitoru
Linux System Administrator
Mobile: +972-5-28704261
Email: eliezer@xxxxxxxxxxxx
-----Original Message-----
From: CentOS [mailto:centos-bounces@xxxxxxxxxx] On Behalf Of Laszlo
Danielisz
Sent: Thursday, August 9, 2018 9:53 PM
To: centos@xxxxxxxxxx
Subject: bad udp cksum
Hi,
Recently I'm noticing an interesting issue.
My CentOS servers are trying to send logs to a logging server via 514/udp,
however I'm not receiving anything.
I did the following on CentOS
*tcpdump -vvv -nn udp -i esn160 port 514*
In another session on the same server:
*nc syslog-server -u 514*
tcpdump started to show me messages like:
*[bad udp cksum 0x3ce9 -> 0xb0f5!] SYSLOG, length: 172*
After some research I disabled TCO (ethtool -K ens160 tx off rx off), now
tcpdump shows:
*[udp sum ok] [|syslog]*
And I'm also receiving the logs. Yay!
I have the same issue on multiple servers with CentOS versions 7.3.1611,
7.4.1708 & 7.5.1804. I'm having the issue no matter if it is a physical or
virtual server (they also use different hardware and NIC's)
Of course I could run ethtool every time a server starts but I think there
should be a better solution. Also I enjoy having TCO giving some rest to
the CPUs.
Did anyone find a solution for this?
Thanks!
Laszlo
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