Handling Dialup Connections

3.30.1 Problem

You're running an authoritative name server behind a dial-on-demand connection.

3.30.2 Solution

Designate the name server's zones as dialup zones using the dialup substatement:

options { directory "/var/named"; dialup yes; };

This tells the name server to concentrate zone maintenance activity into a short period, and to perform that maintenance once each heartbeat interval. The default heartbeat interval is one hour. For a slave zone, the name server will refresh once, at most, during each heartbeat interval, even if the zone's refresh interval is shorter. For a master zone, the name server will send NOTIFY messages to all slaves when the zone changes, triggering a dialup and a successive zone transfer.

3.30.3 Discussion

To adjust the heartbeat interval, use the heartbeat-interval options substatement. For example:

options { directory "/var/named"; heartbeat-interval 180; // 3 hours };

You can also use dialup as a zone substatement, in which case it suppresses zone maintenance traffic for just that zone. This may be useful on a name server that has dedicated connectivity to the Internet, but has a slave or master at the far end of a dialup connection.

3.30.4 See Also

"Running Authoritative Name Servers over Dial-on-Demand" in Chapter 16 of DNS and BIND.