How to exclude given lines in syslog-ng?

Question

I need to exclude a given line in the messages file:

Oct 25 04:09:23 SERVERNAME PFILTER-DROP: IN=ifeth4 OUT= MAC=ff:ff:ff:ff:ff:ff:AA:AA:AA:AA:AA:AA:AA:AA SRC=192.168.202.4 DST=192.168.202.255 LEN=238 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=32776 DPT=705 LEN=218 
Oct 25 04:09:23 SERVERNAME PFILTER-DROP: IN=ifeth4 OUT= MAC=ff:ff:ff:ff:ff:ff:AA:AA:AA:AA:AA:AA:AA:AA SRC=192.168.202.6 DST=192.168.202.255 LEN=183 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=32770 DPT=700 LEN=163 
Oct 25 04:09:23 SERVERNAME PFILTER-DROP: IN=ifeth4 OUT= MAC=ff:ff:ff:ff:ff:ff:AA:AA:AA:AA:AA:AA:AA:AA SRC=192.168.202.8 DST=192.168.202.255 LEN=176 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=32768 DPT=714 LEN=156 
Oct 25 04:09:23 SERVERNAME PFILTER-DROP: IN=ifeth4 OUT= MAC=ff:ff:ff:ff:ff:ff:AA:AA:AA:AA:AA:AA:AA:AA SRC=192.168.202.10 DST=192.168.202.255 LEN=175 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=33628 DPT=715 LEN=155 
Oct 25 04:09:23 SERVERNAME PFILTER-DROP: IN=ifeth4 OUT= MAC=ff:ff:ff:ff:ff:ff:AA:AA:AA:AA:AA:AA:AA:AA SRC=192.168.202.30 DST=192.168.202.255 LEN=185 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=32770 DPT=713 LEN=165 
Oct 25 04:09:23 SERVERNAME PFILTER-DROP: IN=ifeth4 OUT= MAC=ff:ff:ff:ff:ff:ff:AA:AA:AA:AA:AA:AA:AA:AA SRC=192.168.202.34 DST=192.168.202.255 LEN=237 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=32781 DPT=704 LEN=217 

they are afaik heartbeat udp messages, but they aren't needed in the logs.

# rpm -qa | grep -i syslog-ng
Security.syslog-ng-1.6.8.0-1
# uname -a
Linux SERVERNAME 2.6.5-7.325-bigsmp #1 SMP Tue Jan 18 23:36:49 UTC 2011 i686 i686 i386 GNU/Linux
# cat /etc/SuSE-release 
SUSE LINUX Enterprise Server 9 (i586)
VERSION = 9
PATCHLEVEL = 4

Q: How can I exclude these kind of messages from the /var/log/messages?

Solution 1

BEFORE:

SERVER:/etc/syslog-ng # tail -3 syslog-ng.conf
#
#
log { source(src); destination(/var/log/messages); };
SERVER:/etc/syslog-ng # 

EDIT THE syslog-ng.conf FILE:

vi /etc/syslog-ng/syslog-ng.conf

AFTER:

SERVER:/etc/syslog-ng # tail -3 syslog-ng.conf
#log { source(src); destination(/var/log/messages); };
filter heartbeat_filter { not match("PFILTER-DROP") and not match("DST=192.168.202.255") and not match("PROTO=UDP"); }; 
log { source(src); filter(heartbeat_filter); destination(/var/log/messages); };
SERVER:/etc/syslog-ng # 

RESTART SYSLOG-NG

/etc/init.d/syslog restart # or whatever you use to restart syslog-ng
# now check

ROTATE IF NEEDED

logrotate /etc/logrotate.conf

Solution 2

You can use a filter to match the program sending the message, in this case PFILTER-DROP, like this:

filter f_pfilterdrop {
   program("PFILTER-DROP");
};

Then you include this filter in the log statement that writes to this log.

Solution 3

How can I extend this excluding rule to filter only those lines that contain: "DST=192.168.202.255" AND uses "udp" AND "PFILTER-DROP"?

Use something like:

filter demo_filter { program("PFILTER-DROP") and match("DST=192.168.202.255") and match("PROTO=UDP"); };

Comments

[gasko peter]

How can I extend this excluding rule to filter only those lines that contain: "DST=192.168.202.255" AND uses "udp" AND "PFILTER-DROP"?

[Jenny D]

I see somebody else already answered that - glad it seems to be working for you!

[gasko peter]

I tested it and didn't worked, sorry:D

[devarni]

I found that I needed to enclose those matches in parentheses to apply the AND condition properly, e.g. not (match("PFILTER-DROP") and match("DST=192.168.202.255") and match("PROTO=UDP"));. Otherwise it seems to have more of an OR effect.