The general issues to take into consideration when troubleshooting your system are listed below. You should read them carefully before trying to solve more specific problems.
Any script inside a Container could have been changed to whatever the Container owner chooses: it could have been trojaned, replaced to something like
rm -rf, etc. You can use only
pctl exec/pctl enter to execute programs inside a Container.
- Do not use init scripts on the server. An init script may use
killall to stop a service, which means that all similar processes will be killed in all Containers. You can check
/var/run/Service.pid and kill the correspondent process explicitly.
- You must be able to detect any rootkit inside a Container. It is recommended to use the
chkrootkit package for detection (you can download the latest version from www.chkrootkit.org), or at least run
rpm -Va|grep "S.5"
to check up if the MD5 sum has changed for any RPM file.
You can also run
nmap, for example:
# nmap -p 1-65535 192.168.0.1
Starting nmap V. 2.54BETA22 ( www.insecure.org/nmap/ )
Interesting ports on (192.168.0.1):
(The 65531 ports scanned but not shown below are in
Port State Service
21/tcp open ftp
22/tcp open ssh
80/tcp open http
111/tcp open sunrpc
Nmap run completed -- 1 IP address (1 host up) scanned
in 169 seconds
to check if any ports are open that should normally be closed.
That could however be a problem to remove a rootkit from a Container and make sure it is 100% removed. If you're not sure, create a new Container for that customer and migrate his/her sites and mail there.
- Check the
/var/log/ directory on the server to find out what is happening on the system. There are a number of log files that are maintained by the system and Parallels Server Bare Metal (the
messages, etc.), but other services and programs may also put their own log files here depending on your distribution of Linux and the services and applications that you are running. For example, there may be logs associated with running a mail server (the
maillog file), automatic tasks (the
cron file), and others. However, the first place to look into when you are troubleshooting is the
/var/log/messages log file. It contains the boot messages when the system came up as well as other status messages as the system runs. Errors with I/O, networking, and other general system errors are reported in this file. So, we recommend that you read to the
messages log file first and then proceed with the other files from the
- Subscribe to bug tracking lists. You should keep track of new public DoS tools or remote exploits for the software and install them into Containers or at servers.
- When using
iptables, there is a simple rule for Chains usage to help protect both the server and its Containers:
- use INPUT, OUTPUT to filter packets that come in/out the server
- use FORWARD to filter packets that are designated for Containers