Procedure for solving DNS issues

clearosOccasionally I get DNS issues, which results in the entire site losing internet connectivity. This article describes processes that I've used to fix this problem.


DNS override

Log on to ClearOS dashboard.

  1. Go to Network > Settings > IP Settings.
  2. In the DNS section, click the Temporary Override button.
  3. Add the following Google Public DNS IP addresses for DNS Server #1 and #2
8.8.8.8
8.8.4.4

 

/etc/resolv.conf

I have found that this file can get overwritten sometimes. Start by accessing the server using SSH. Create a copy of /etc/resolve.conf file for backup. Open /etc/resolv.conf for editing. Settings that worked for me are:

search lan mydomain.local
nameserver 192.168.1.254

 Where the IP address represents the router.

 

DHCP Server

It's important that clients are receiving the correct DNS information from the DHCP Server. Log on to ClearOS dashboard.

  1. Go to Network > Infrastructure > DHCP Server.
  2. Click Edit for the subnet that represents your internal LAN.
  3. For DNS #1 enter the IP address of your ClearOS server as seen from the Internal LAN.

 

Thanks for visiting.