Jabber Mobile and Remote Access is heavily reliant on DNS. The biggest impact of this is that a lot of Cisco UC implementations may not utilize DNS. CUCM node names may be configured using IP addresses or hostnames, rather than FQDN. Jabber MRA does not require the use of FQDNs; however, after 2016 public CAs will require that Common Names and Subject Alternative Names must be publicly resolvable or the CAs won’t issue certificates for those hosts.
Jabber MRA will require the following internal DNS records and external DNS records:
| APPLICATION | INTERNAL RECORDS | EXTERNAL RECORDS | TARGET ADDRESS | UCC Cert |
| CUCM Servers | A, PTR, SRV | none | LAN IP Address | Y |
| CUC Servers | A & PTR | none | LAN IP Address | Y |
| IM&P Servers | A, PTR, SRV | none | LAN IP Address | Y |
| CCx servers | A & PTR | none | LAN IP Address | Y |
| Expressway E | A & PTR | A,PTR, SRV | Public IP Address | Y |
| Expressway C | A & PTR | none | LAN IP Address | Y |
| collab-edge | none | A | Public IP Address | Y |
