dhcpcd[xxxx]: br0/eth1: Router Advertisement from <IPv6> floods syslog


mgutt

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It creates a new log entry every 5 to 10 minutes:

99911810_2021-08-1611_57_35.thumb.png.320bba58e1c300fa79f9ca4e8f7ad341.png

 

These are my network settings:

1809934794_2021-08-1611_59_34.thumb.png.b719b37d21b9ab1ea8c2872afa878a22.png

 

As I understand it right its something like a "heartbeat" which is pretty normal with an IPv6 DHCP server. The suggestion is a) to set noipv6rs in the dhcp servers config, which I'm not able to do as my router doesn't allow it (and I'm not sure if this would break something) or b) to filter out those messages on the client:

https://unix.stackexchange.com/questions/273818/can-i-stop-ipv6-router-advertisement-filling-syslog-without-disabling-ipv6

 

So I tried to solved this issue by adding this to the /boot/config/rsyslog.conf

# stop IPv6 router advertisement messages
:msg, contains, "Router Advertisement from" stop

image.png.dc2673d4657becfbd2342d694cc9c97f.png

 

And restarting the rsyslog daemon:

/etc/rc.d/rc.rsyslogd restart

 

But the messages were still added to the logs 🤷‍♂️

 

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I stopped these messages by setting "Enable Router Advertisement" to disabled in my ASUS router.

 

There is an issue with the syslog filtering setup in rsyslog.conf.  I solved the issue with the Enhanced Log plugin so it will work properly.  Install the plugin and then set up the syslog filter to what you want with the plugin.

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On 8/16/2021 at 3:23 PM, bonienl said:

The rsyslog.conf on your USB stick is copied at system start up to /etc/rsyslog.conf

Good to know, but does not work either. I even tried to add the filter to the top of the file because I thought it could be related to this bug:

image.png.5b1b1b902a236153b38fcb888c43e2e6.png

 

image.png.85a2ceb7681ee528ccf4cdfef4ee4c24.png

 

 

 

EDIT:

 

It works only if the rule is added after the "$RuleSet local" line, so I added this to my Go file:

# -------------------------------------------------
# Suppress IPv6 Router Advertisement logs
# -------------------------------------------------
sed -i '/$RuleSet local/a:msg,contains,"Router Advertisement from" stop' /etc/rsyslog.conf
/etc/rc.d/rc.rsyslogd reload

 

 

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