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MithiWiki Home > ConnectXf Home > ConnectXf Administration > Configuration > On configuring DRBD/Heartbeat setup, after configuring the Virtual IP to be the one which was earlier assigned to the primary machine, outgoing mailing stopped working


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Troubleshooting
Product ConnectXf
Version All
Applies to Administrators
Level Advanced




On configuring DRBD/Heartbeat setup, after configuring the Virtual IP to be the one which was earlier assigned to the primary machine, outgoing mailing stopped working

Symptoms

  • The outgoing mails to external domains are not going and the /var/log/maillog shows "CNAME lookup failure" as the error message
  • When the dig command is executed from the server using the virtual IP it works.
dig -x gmail.com -b <Virtual IP>
  • When the dig command is executed from the server using the real IP assigned to etho, it fails to resolve the domain
dig -x gmail.com -b <Real IP assigned to eth0 of the primary server>

Cause

  • The DNS requests to the DNS server are sent out using the IP assigned to eth0, the firewall is blocking the requests for the real IP but allowing requests from the virtual IP.
  • Since the DNS cannot resolve the domain names, external mail are not delivered

Workaround

  • Switch the real IP of the primary and the virtual IP, till the firewall is reconfigured. This ensures that the DRBD and heartbeat is configured.
  • However auto switchover will not work

Solution

  • The firewall/other network elements should allow outgoing DNS requests on port 53 for all the following IPs:
    • The virtual IP
    • The real IP assigned to the primary server
    • The real IP assigned to the secondary server