csf SMTP_BLOCK option
This option will help prevent the most common form of spam abuse on a server that bypasses exim and sends spam directly out through port 25. Enabling this option will prevent any web script from sending out using socket connection, such scripts should use the exim or sendmail binary instead
Block outgoing SMTP except for root, exim and mailman (forces scripts/users to use the exim/sendmail binary instead of sockets access).
This replaces the protection as WHM > Tweak Settings > SMTP Tweaks
This option uses the iptables ipt_owner module and must be loaded for it to work. It may not be available on some VPS platforms
Note: Run /etc/csf/csftest.pl to check whether this option will function on this server
If SMTP_BLOCK is enabled but you want to allow local connections to port 25 on the server (e.g. for webmail or web scripts) then enable this option to allow outgoing SMTP connections to the loopback device
How to check if csf will work on your server
One you have downloaded CSF firewall and installed it, you can run the below command to check the status and the results.
# /etc/csf/csftest.pl
Testing ip_tables/iptable_filter…OK
Testing ipt_LOG…OK
Testing ipt_multiport/xt_multiport…OK
Testing ipt_REJECT…OK
Testing ipt_state/xt_state…OK
Testing ipt_limit/xt_limit…OK
Testing ipt_recent…OK
Testing ipt_owner…OK
Testing iptable_nat/ipt_REDIRECT…OK
RESULT: csf should function on this server
Modified cPanel addons are not allowed message
Sorry modified cPanel addons are not allowed, contact your server admin for more info.
To resolve this issue:
1. Login to the WHM.
2. Click on ‘Tweak Settings’
3. Remove the ticks from the below options:
- Prevent installation of addon scripts not provided by cPanel
- Prevent installation of cPanel addon scripts that have be altered (Turning this off may be useful when testing custom addons.)
This should fix the problem.
cPanel’s DNS clustering
cPanel’s DNS clustering allows you to synchronize DNS records between multiple cPanel or cPanel DNS ONLY machines. In order to synchronize your DNS records, all machines in the cluster must be running cPanel or cPanel DNS ONLY versions 8.9 or higher.
When configuring your server cluster, it is important to minimize the amount of hops between servers to create the shortest path possible. When possible, you should link webserver server directly to your dns servers or any other servers you wish to update. Each time a DNS zone is modified, the modification will travel down the path to reach each server in the path. The performance of the system is directly proportional to the length of the path.
Notes:
Synchronize Changes: All changes made on your webserver server will be replicated to any server linked to the webserver in the cluster.
Synchronization is one-way: Changes made on the other server will not be replicated to webserver server unless Synchronize Changes is selected on that server as well.
Standalone: All changes made on webserver server will not replicated to any other server(s).
Apache Memory Usage Restrictions in WHM
Main >> Service Configuration >> Apache Configuration
This function will calculate your apache memory usage based on your memory usage history and set a new memory limit for Apache processes. Limiting each process’ access to memory will increase the stability of your server but may reduce performance slightly. This is a limit for each Apache process, not for all Apache processes combined.
Click the Proceed button to activate this feature
For more information about this feature, see http://httpd.apache.org/docs/2.0/mod/core.html#rlimitmem
This will add a line to httpd.conf
#Rlimit added by apachelimits.pl
RLimitMEM 148015786
