Nortel SCS User Manual page 36

Disaster recovery
DNS SRV records
DNS Service (DNS SRV) records allow a phone on your network to query the DNS server for the host that is responsible for SIP
signaling. The DNS server returns the fully qualified name of the SCS server. Use of DNS SRV records is the preferred choice for
enterprise deployment, as it allows SIP users to compile an address without knowing the server name; the domain name is sufficient.
Examples of SIP addresses for users of lines are as follows:
• sip:joe@domain.com
• sip:200@domain.com
By default, SCS uses a fully qualified host name without using DNS SRV. If you choose to install DNS on the same server as the SCS,
the following steps will be taken care of be default.
To ensure that DNS SRV is running on your system, perform the following steps:
1 To verify DNS name resolution, type the following at a command prompt:
ping scs.yourdomain.com
2 Press Enter.
3 If the ping command replies and display statistics, run a DNS lookup utility test by typing the following at a command prompt:
dig -t A scs.yourdomain.com
4 Press Enter.
5 If the lookup returns an answer, run an SRV test by typing the following at a command prompt:
dig -t SRV _sip._tcp.yourdomain.com
6 Press Enter.
7 If the lookup returns an answer, run another SRV test by typing the following at a command prompt:
dig -t SRV _sip._udp.yourdomain.com
8 Press Enter.
9 IF the lookup returns an answer, run a final SRV test by typing the following at a command prompt:
dig -t SRV _sips._tcp.yourdomain.com
10 Press Enter.
11 If all results are correct, your DNS server is running properly, as are the SRV records. If any tests fail, contact your DNS
administrator, or seeBind documentation for Linux for Server documentation for Microsoft to properly set up your DNS.
Page 24 Software Communication System v1.0 2007 Nortel