Network Management & Monitoring

Log management, part I : Using syslog-ng
----------------------------------------

Notes:
------
* Commands preceded with "$" imply that you should execute the command as
  a general user - not as root.
* Commands preceded with "#" imply that you should be working as root.
* Commands with more specific command lines (e.g. "RTR-GW>" or "mysql>") 
  imply that you are executing commands on remote equipment, or within 
  another program.

Exercises
---------

The routers are able to send syslog messages to multiple destinations,
so that 1 router can send messages to 4 or even 5 destinations.
We therefore need to configure the router to send messages to each of
the PCs in the group.

1. Configure your virtual routers to send syslog messages to your server:

You will log in to your group's router and do the following:

	$ ssh 10.10.X.254
	rtrX.ws.nsrc.org> enable
	rtrX.ws.nsrc.org# config terminal

	rtrX.ws.nsrc.org(config)# logging 10.10.X.Y

	... where X.X is the IP of your PC (group + number).

	rtrX.ws.nsrc.org(config)# logging facility local5
	rtrX.ws.nsrc.org(config)# logging userinfo
	rtrX.ws.nsrc.org(config)# exit
	rtrX# write memory

Now run "show logging" to see the summary of the log configuration.

The other participants in your group will be doing the same thing,
so you should not be surprised if you see other destinations as well
in the output of "show logging"

	logout from the router (exit)

	rtrX# exit

That's it. The router should now be sending UDP SYSLOG packets to your PC
on port 514.

To verify this log in on your PC and do the following:

	$ sudo bash
	# tcpdump -e -s0 -ni eth0 port 514

Then have one person in your group log back in on the router and do the
following:

	$ ssh 10.10.X.254
	rtrX.ws.nsrc.org> enable
	rtrX.ws.nsrc.org# config terminal
	rtrX.ws.nsrc.org(config)# exit
	rtrX.ws.nsrc.org> exit

You should see some output on your PC's screen from TCPDUMP. It should look
something like:

02:20:24.942289 ca:02:0d:b3:00:08 > 52:54:4a:5e:68:77, ethertype IPv4 (0x0800), length 144: 10.10.0.6.63515 > 10.10.0.250.514: SYSLOG local5.notice, length: 102
02:20:24.944376 ca:02:0d:b3:00:08 > c4:2c:03:0b:3d:3a, ethertype IPv4 (0x0800), length 144: 10.10.0.6.53407 > 10.10.0.241.514: SYSLOG local5.notice, length: 102

Now you can configure the logging softeware on your PC to receive this
information and log it to a new set of files:


2. Configure rsyslog

Edit file /etc/rsyslog.conf and find and change the following lines:

	#$ModLoad imudp
	#$UDPServerRun 514

to

	$ModLoad imudp
	$UDPServerRun 514

(remove #)

Then change:

	$PrivDropToUser syslog
	$PrivDropToGroup syslog

to

	#$PrivDropToUser syslog
	#$PrivDropToGroup syslog

Finally add the lines:

	$template RouterLogs,"/var/log/network/%$YEAR%/%$MONTH%/%$DAY%/%HOSTNAME%-%$HOUR%.log" 
	local5.*            -?RouterLogs

Save and exit, then:

	# mkdir /var/log/network
	# chown syslog /var/log/network

4. Restart rsyslog

	# service rsyslog restart

6. On your PC, See if messages are starting to appear under

	/var/log/network/2011/.../

7. If not, try to login back into the router, and run some "config" commands,
   then logout. I.E.

	# ssh 10.10.X.254
	rtrX.ws.nsrc.org> enable
	rtrX.ws.nsrc.org# config terminal
	rtrX.ws.nsrc.org(config)# exit
	rtrX.ws.nsrc.org> exit

Be sure you log out of the router when you are finished.
If too many people log in without logging out then others cannot gain access
to the router.

Other commands to try while you are logged into the router, in config mode:

- shutdown / no shutdown the Loopback interfaces, for example:

	rtrX# conf t
	rtrX(config) # interface Loopback 999
	rtrX(config-if) # shutdown

	wait a few seconds

	rtrX(config-if) # no shutdown

	Then exit, and save the config ("write")


Check the logs under /var/log/network

What other commands can you think of that you can run on the
router (BE CAREFUL!) that will trigger syslog messages ?

What about access lists ?

Others ?