Wondering how to disable the portmapper services? We can help you.

Recently, one of our customers received a report stating his server is vulnerable to portmapper attacks.

As part of our Server Management Services, we assist our customers with several cPanel queries.

Today, we will see how our support engineers fix the issue with port 111.

Disable the portmapper services

cPanel & WHM does not use and manage rpcbind. It is a system process. Generally, it relates to NFS mounts.

If the server does not have any of these mounts, most often, it is easy for the systems administrator to disable the service.

Moving ahead, let us see how our Support Techs perform the same.

Initially, to stop the rcpbind service, run the following commands as root:

systemctl stop rpcbind
systemctl stop rpcbind.socket

Then, we have to disable the service. We do this to ensure it does not start when the server reboots.

To do so, we run the following command:

systemctl disable rpcbind

In addition, we can block the port with the server’s firewall or a network firewall. However, this should not impact the cPanel & WHM related services.

To see if the port is open, we run the following command against the server’s IP address:

nmap -Pn -sU -p U:111 --script=rpcinfo 192.0.2.0

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Conclusion

In short, if the server does not have any mounts, administrators can disable the portmapper services. In this article, we saw how our Server Administrators perform the same.