Article ID: 126712, created on Aug 28, 2015, last review on Aug 28, 2015

  • Applies to:
  • Plesk 12.0 for Linux
  • Plesk 11.5 for Linux


Master server with Plesk is running behind NAT. Slave DNS server is running outside of the internal network and has public IP.

Slave DNS server could not update any zones from Master server.

The following error is present in the /var/log/syslog file on the slave DNS server:

    named[4195]: transfer of 'domain.tld/IN' from <internal Master DNS ip>#53: failed to connect: host unreachable


Despite all DNS records are correct and pointed to the public IP, in the zones config, master server still has internal IP . When master server sends request to update to the slave server, slave server tries to connect to the master server as per received zone config to the internal IP i.e.

Since IP address is unreachable from the slave's network it is failing with the mentioned error.


Add two iptables rules to ensure all outgoing traffic redirection from internal to public

    iptables -t nat -A OUTPUT -d -p udp -j DNAT --to-destination
    iptables -t nat -A OUTPUT -d -p tcp -j DNAT --to-destination

Search Words

53: failed to connect: host unreachable

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