Red Hat Enterprise Linux - Allow Root Login From a Specific IP Address Only

Title: Red Hat Enterprise Linux - Allow Root Login From a Specific IP Address Only
Object Name: mmr_kc-0119626
Document Type: Support Information
Original owner: KCS - Linux
Disclosure level: Public
Version state: final
FACT:Red Hat Enterprise Linux
GOAL:Restrict root SSH login to a single IP address
FIX:This can be accomplished with the use of PAM access controls.  There are two steps:

1. In /etc/pam.d/sshd, add the following line:

account    required

2. In /etc/security/access.conf, set up root access controls by adding the following two lines at the end of the file:

+ : root : IP_address
- : root : ALL

Replace "IP_address" with the IP address of the system from which root logins will be allowed.  Note that there is a space before and after each colon.  The first line allows root access from the specified IP address; the second line denies root access from everywhere else.  The order of these two lines is significant.  This will take effect immediately with no need to reboot or restart any daemons.

Login attempts that are blocked by this check will be logged in /var/log/secure:

Jul 15 16:51:42 hostname sshd[18241]: fatal: Access denied for user root by PAM account configuration

This method of access control is very flexible and powerful.  For example, if you should need to add a second allowed host at some point in the future, simply add its IP address to the first line:

+ : root : IP_address_1 IP_address_2
- : root : ALL

There are many other options, which are well documented within the access.conf file itself or its reference page.
0 (0)
Article Rating (No Votes)
Rate this article
There are no attachments for this article.
There are no comments for this article. Be the first to post a comment.
Full Name
Email Address
Security Code Security Code
Related Articles RSS Feed
Exclude multiple files and directories with rsync
Viewed 486 times since Wed, Oct 31, 2018
LVM: Move allocated PE between Physical Volumes
Viewed 763 times since Sat, Jun 2, 2018
RHEL: Getting/Setting hardware clock’s time
Viewed 925 times since Sat, Jun 2, 2018
Deskshare TLS over Stunnel
Viewed 448 times since Fri, Sep 28, 2018
What Is /dev/shm And Its Practical Usage
Viewed 585 times since Tue, Mar 12, 2019
stunnel Howto A Guide to create SSL access to a HTTP-only webserver with stunnel
Viewed 458 times since Fri, Sep 28, 2018
RHCS6: Reduce a Global Filesystem 2 (GFS2)
Viewed 589 times since Sun, Jun 3, 2018
How to sort IP addresses in Linux
Viewed 1015 times since Sun, May 20, 2018
Linux – How to check the exit status of several piped commands
Viewed 1156 times since Wed, Jul 25, 2018
SSL HowTo: Decode CSR
Viewed 471 times since Mon, Feb 18, 2019