rsyslog - Property-based filtering not working - linux

Question

I almost hate to submit a topic for this, but I haven't been able to figure it out on my own. I'm running a Federoa 17 server, and I'm attempting to log dropped packets from iptables to a separate log file via rsyslog, but it keeps sending them to /var/log/messages instead.
Snippet from my firewall script:
#!/bin/bash
iptables -F
# My accepted rules would be here
iptables -A INPUT -j LOG --log-prefix "iptables: "
iptables -A FORWARD -j LOG --log-prefix "iptables: "
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
iptables-save > /etc/sysconfig/iptables
service iptables restart
iptables -L -v
The config file that SHOULD be catching the messages from iptables:
[root#fc17 ]# cat /etc/rsyslog.d/iptables.conf
:msg, startswith, "iptables: " /var/log/iptables.log
& ~
Snippet from my rsyslog.conf file:
#### GLOBAL DIRECTIVES ####
# Include all config files in /etc/rsyslog.d/
$IncludeConfig /etc/rsyslog.d/*.conf
#### RULES ####
# I put this in here too to see if it would work; it doesn't
:msg, startswith, "iptables: " /var/log/iptables.log
& ~
# Log all kernel messages to the console.
# Logging much else clutters up the screen.
#kern.* /dev/console
# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;authpriv.none;cron.none /var/log/messages
I've restarted both iptables and rsyslog multiple times since making the changes, and no matter what, it will only only log dropped packets from iptables to /var/log/messages.
I heard running rsyslog in compatibility mode can cause various problems. Could this be the case here? Here are its run-options on my system:
[root#fc17 ]# ps -ef | grep rsyslog
root 3571 1 0 00:59 ? 00:00:00 /sbin/rsyslogd -n -c 5

Answer 1

startswith comparison operator didn't work,because msg didn't begin with iptables: when i checked my logs.
[root#localhost ~]# cat /etc/rsyslog.d/test.conf
:msg, startswith, "iptables:" /var/log/iptables.log
but contains comparison operator worked on my FC18
[root#localhost ~]# cat /etc/rsyslog.d/test.conf
:msg, contains, "iptables:" /var/log/iptables.log
Ref: Rsyslog site

Answer 2

you should add the following two line in your "/etc/rsyslogd.conf" in directives part
$klogParseKernelTimestamp on
$klogKeepKernelTimestamp off
This will remove the kernel timestamp which appears in the begining of every kernel message like "[6448.546951]" in the following log
Mar 31 14:36:14 localhost kernel: [ 6448.546951] iptables: IN=ppp0 OUT= MAC= SRC=

Answer 3

2019 solution. Tested with rsyslogd 8.32.0 on Ubuntu18.04.
You can still use startswith,
[root#localhost ~]# cat /etc/rsyslog.d/test.conf
:msg, startswith, " iptables:" /var/log/iptables.log
by changing the line in /etc/rsyslogd.conf
module(load="imklog" ParseKernelTimestamp="on" KeepKernelTimestamp="off")

Answer 4

I'm using rsyslogd 5.8.10 over centos 6, my log report show this way:
Aug 12 11:50:41 node2 kernel: [10256396.525411] IPTables-Dropped: IN=eth0 OUT= MAC=00:25:90:c3:05:40:00:24:13:10:8c:00:08:00 SRC=212.237.40.56 DST=37.153.1.29 LEN=45 TOS=0x00 PREC=0x00 TTL=244 ID=54321 PROTO=UDP SPT=45661 DPT=53413 LEN=25
I tried to disabled the timestamp with:
$klogParseKernelTimestamp on
$klogKeepKernelTimestamp off
But show:
Aug 12 11:50:22 node2 rsyslogd-3003: invalid or yet-unknown config file command - have you forgotten to load a module? [try http://www.rsyslog.com/e/3003 ]
In modules have this:
#### MODULES ####
$ModLoad imuxsock # provides support for local system logging (e.g. via logger command)
$ModLoad imklog # provides kernel logging support (previously done by rklogd)
#$ModLoad immark # provides --MARK-- message capability
Thank you advance.