Syslog

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Syslog-ng install

apt-get install syslog-ng

Example of /etc/syslog-ng/syslog-ng.conf:

Comment kernel source out as we are in a vserver: 

   source s_all {
       #file("/proc/kmsg" log_prefix("kernel: "));

I want to keep the original hostnames: 

   options {
       keep_hostname(1);

Enable logging per remote host 

   source net { udp(ip(192.168.x.xxx)); };
   destination df_zeus    {   file("/var/log/syslog-zeus.log"    owner("root") group("adm") perm(0640)); };
   destination df_public  {   file("/var/log/syslog-public.log"  owner("root") group("adm") perm(0640)); };
   destination df_private {   file("/var/log/syslog-private.log" owner("root") group("adm") perm(0640)); };
   destination df_ns0     {   file("/var/log/syslog-ns0.log"     owner("root") group("adm") perm(0640)); };
   destination df_sql     {   file("/var/log/syslog-sql.log"     owner("root") group("adm") perm(0640)); };
   destination df_others  {   file("/var/log/syslog-$HOST.log"   owner("root") group("adm") perm(0640)); };
   filter f_zeus    { host(192.168.x.xxx); };
   filter f_public  { host(192.168.x.xxx); };
   filter f_private { host(192.168.x.xxx); };
   filter f_ns0     { host(192.168.x.xxx); };
   filter f_sql     { host(192.168.x.xxx); };
   filter f_others  { not host(192.168.x.xxx) and not host(192.168.x.xxx) and not host(192.168.x.xxx) and not host(192.168.x.xxx) and not host(192.168.x.xxx) };
   log { 
       source(net);
       filter(f_zeus);
       destination(df_zeus);
   };
   log {
       ...

Allow inbound connections from monitoring subnet 

iptables -A INPUT -s xxxx -d xxxx -p udp --dport 514 -m state --state NEW -j ACCEPT

On satellite hosts: add to /etc/syslog.conf

  • .* @192.168.x.xxx

Resources & Credits


Logcheck

apt-get install logcheck logcheck-database

In /etc/logcheck/logcheck.conf: 

REPORTLEVEL="paranoid"

Tuning logcheck filters

Solving the issue at the source

I have many such messages in the vserver: 

pam_limits[863]: setrlimit limit #6 to soft=-1, hard=-1 failed: Operation not permitted; uid=0 euid=0

Not sure why, probably because vserver max limits are reduced.
To get rid of it, comment the line in /etc/pam.d/cron and /etc/pam.d/ssh: 

#session    required     pam_limits.so

Writing and testing new rules

Add your rules into files prepend by "local-" to distinguish your own rules.
Be sure to tune ownership and rights of those new files so that user logcheck can read them.
e.g. rw-r----- root:logcheck

To test logcheck filtering rules: 

sed -e 's/[[:space:]]*$//' <logfile> | egrep '<regexp>'

Then you can dry run logcheck on the command line: 

su logcheck -s /bin/bash -c "/usr/sbin/logcheck -l <logfile> -o -t"

This is easier if you have sudo installed...

Examples of home-made rules

For common imapd timeouts: 

/etc/logcheck/ignore.d.paranoid/local-imap:
^\w{3} [ :0-9]{11} [._[:alnum:]-]+ imapd: TIMEOUT, user=[a-z]+, ip=\[[:.0-9a-f]+\], headers=0, body=0, rcvd=[0-9]+, sent=[0-9]+, time=[0-9]+, starttls=1$

TODO

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