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
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
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@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@centos.org https://lists.centos.org/mailman/listinfo/centos
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@ngtech.co.il
-----Original Message----- From: CentOS [mailto:centos-bounces@centos.org] On Behalf Of Laszlo Danielisz Sent: Thursday, August 9, 2018 9:53 PM To: centos@centos.org Subject: [CentOS] 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 _______________________________________________ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Well, it is in general a good idea to disable all the fancy nic feature like tso, gro, rx/tx offload if strange things happen
-----Ursprüngliche Nachricht----- Von: CentOS centos-bounces@centos.org Im Auftrag von Eliezer Croitoru Gesendet: Donnerstag, 6. September 2018 13:51 An: 'CentOS mailing list' centos@centos.org Betreff: Re: [CentOS] bad udp cksum
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@ngtech.co.il
-----Original Message----- From: CentOS [mailto:centos-bounces@centos.org] On Behalf Of Laszlo Danielisz Sent: Thursday, August 9, 2018 9:53 PM To: centos@centos.org Subject: [CentOS] 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 _______________________________________________ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
_______________________________________________ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
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Eliezer Croitoru -
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