Manual

Appendix 2: DNS records
DNS configuration on host server
The following records are required in the external DNS which hosts the externally routable domain:
example.com to allow messages from non-registered endpoints (or other infrastructure devices) to be routed
to the Expressway-E
Host DNS A record
Host Host IP address
expe.example.com 192.0.2.2
DNS SRV records
Name Service Protocol Priority Weight Port Target host
example.com. h323cs tcp 10 10 1720 expe.example.com.
example.com. h323ls udp 10 10 1719 expe.example.com.
example.com. sip tcp 10 10 5060 expe.example.com.
example.com. sip udp * 10 10 5060 expe.example.com.
example.com. sips tcp 10 10 5061 expe.example.com.
example.com. turn udp 10 10 3478 ** expe.example.com.
* SIP UDP is disabled on Expressway by default.
** On Large VM server deployments you should configure multiple records for the range 3478 – 3483.
For example, the DNS records would be:
_h323cs._tcp.example.com. 86400 IN SRV 10 10 1720 expe.example.com.
_h323ls._udp.example.com. 86400 IN SRV 10 10 1719 expe.example.com.
_sip._tcp.example.com. 86400 IN SRV 10 10 5060 expe.example.com.
_sip._udp.example.com. 86400 IN SRV 10 10 5060 expe.example.com.
_sips._tcp.example.com. 86400 IN SRV 10 10 5061 expe.example.com.
_turn._udp.example.com. 86400 IN SRV 10 10 3478 expe.example.com.
expe.example.com. 86400 IN A 192.0.2.2
If you have a cluster of Expressway-Es, you must set up DNS A and SRV records for each peer/host in the
cluster. See Expressway Cluster Creation and Maintenance Deployment Guide for more information.
DNS configuration (internal DNS server)
The following records are required in the local DNS which hosts the internally routable domain: internal-
domain.net to allow internal messages to be routed to the Expressway-C.
Cisco Expressway Basic Configuration Deployment Guide (X8.5.2) Page 40 of 57
Appendix 2: DNS records