ifup-post ignores PEERDNS=no and updates /etc/resolv.conf

Solution Verified - Updated 2024-06-14T15:17:35+00:00 -

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Environment

• Red Hat Enterprise Linux (RHEL) 7.5
• initscripts-9.49.41-1.el7.x86_64

Issue

Script /etc/sysconfig/network-scripts/ifup-post is updating /etc/resolv.conf even though PEERDNS=no is in the ifcfg-* files.

The behavior got broken in RHEL 7.5, worked in RHEL 7.4.

Resolution

Please update initscripts package to initscripts-9.49.41-1.el7_5.2 released with Advisory RHBA-2018:2764 or newer.

Root Cause

In initscripts-9.49.41-1.el7 a condition for handling the RESOLV_MODS option was not defined correctly. As a consequence, the /etc/resolv.conf file could be updated even if the PEERDNS option was set to no. The condition has been fixed in initscripts-9.49.41-1.el7_5.2 and newer releases.

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