[CentOS] bad udp cksum

[Laszlo Danielisz]

I could, however that is going to increase the CPU load, mostly under heavy
network load.

On Fri, Aug 10, 2018 at 3:34 AM, Simon Matter <simon.matter at invoca.ch>
wrote:

> > 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?
>
> You can configure the ETHTOOL_OPTS option in the ifcfg files to
> automatically assign settings on startup.
>
> Regards,
> Simon
>
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
>