TANDBERG Gatekeeper - Manual (Page 94)

TANDBERG Gatekeeper User Guide
Page 94 of 105
17. Appendix A: Configuring DNS Servers
In the examples below, we set up an SRV record to handle H.323 URIs of the form [email protected]
These are handled by the system with the fully qualified domain name of gatekeeper1.example.com
which is listening on port 1719, the default registration port.
It is assumed that an A record already exists for gatekeeper1.example.com. If not, you will need to add
one.
17.1. Microsoft DNS Server
It is possible to add the SRV record using either the command line or the MMC snap-in. To use the
command line: on the DNS server open a command window and enter
dnscmd . /RecordAdd domain service_name SRV service_data
Where:
domain
is the domain into which you wish to insert the record
service_name
is the name of the service you're adding
service_data
is the priority, weight, port and server providing the service as defined by RFC
2782 [3].
For example:
dnscmd . /RecordAdd example.com _h323ls._udp SRV 1 0 1719
gatekeeper1.example.com
17.1.1. BIND 8 & 9
BIND is a commonly used DNS server on UNIX and Linux systems. Configuration is based around two
sets of text files:
named.conf
which describes which zones are represented by the server, and a
selection of zone files which describe the detail of each zone.
BIND is sometimes run chrooted for increased security. This gives the program a new root directory,
which means that the configuration files may not appear where you expect them to be. To see if this is
the case on your system, run
ps aux grep named
This will give the command line that named (the BIND server) was invoked with. If there is a
-t
option,
then the path following that is the new root directory and your files will be located relative to that root.
In
/etc/named.conf
look for a directory entry within the options section. This will give the directory in
which the zone files are stored, possibly relative to a new root directory. In the appropriate zone section,
a file entry will give the name of the file containing the zone details.
For more details of how to configure BIND servers. and the DNS system in general see [6]
17.2. Verifying the SRV Record
There are a range of tools available to investigate DNS records. One commonly found on Microsoft
Windows and UNIX platforms is
nslookup
. Use this to verify that everything is working as expected.
For example:
nslookup -querytype=srv _h323ls._udp.example.com
and check the output.