Linux Administration Cookbook

Changing the listen address

By default, SSH will listen on all addresses and interfaces:

#AddressFamily any#ListenAddress 0.0.0.0#ListenAddress ::

We're going to change this so that it's listening on only IPv4 and our eth1 address.

Change the preceding options to the following:

AddressFamily inetListenAddress 192.168.33.11#ListenAddress ::

We've uncommented two of the options and changed their values.

In the preceding block, you may have noticed that ListenAddress :: is also listed. Here, :: is the IPv6 equivalent of 0.0.0.0 in IPv4.

Restart the SSH daemon:

[vagrant@centos2 ~]$ sudo systemctl restart sshd

Running our ss command from before, you may notice that the IPv6 option has disappeared:

[vagrant@centos2 ~]$ ss -nl sport = :2222Netid ...