How to disable SSH access from everywhere except for certain IPs in CentOS 7

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Here’s how to do it:

firewall-cmd --zone=internal --add-service=ssh --permanent
firewall-cmd --zone=internal --add-source=1.2.3.4/32 --permanent
firewall-cmd --zone=internal --add-source=5.6.7.8/32 --permanent
firewall-cmd --zone=public --remove-service=ssh --permanent

firewall-cmd --reload

This declares an internal zone with two IPs (add as many or as few as you like) and subsequently removes the SSH service from the public zone altogether. As a result, any other IP gets a message such as “Connection refused” when trying to connect via SSH.

The “–permanent” switch saves the changes. Remove it for testing or if you don’t want this change to be permanent.

The last line reloads the current firewall rules (thanks, CertDepot).



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6 thoughts on “How to disable SSH access from everywhere except for certain IPs in CentOS 7”

  1. The basics could be read here: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/sect-Security_Guide-TCP_Wrappers_and_xinetd-TCP_Wrappers_Configuration_Files.html

    Following your example:

    /etc/hosts.allow:
    sshd : 1.2.3.4/32, 5.6.7.8/32

    /etc/hosts.deny:
    sshd: ALL

    —————–

    You can restrict access to a wide variety of daemons. You can know whether a daemon supports or not tcp wrappers with the following command:

    $ ldd /usr/sbin/sshd | grep wrap
    libwrap.so.0 => /lib64/libwrap.so.0 (0x00007fe777cbf000)

    If libwrap is a dynamic dependency, tcp wrappers are supported.

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