Snom ONE IP Technical Manual page 153

6. Account: The account is typically the main DID on the trunk.
7. Domain: The domain is typically the upstream registration server or SIP server.
It can be an IP address or a domain name.
Example: sip.itsp.com
If the service provider is using DNS SRV records, it could be itsp.com.
8. Username: The user name and password are used for authentication purposes
(not all registrars require a different username for authentication).
9. Password: The password needs to match the password from the trunk pro-
vider.
10. Password (repeat): Confirmation of the password.
11. Proxy Address: This setting defines where requests that are made of this trunk
will be sent. When this field is set, requests will be sent to the specified address.
Otherwise, the dial plan replacement field will be used to route the request.
Example: sip.messagenet.it:5061
The outbound proxy field follows the definitions of RFC 3263 ("Locating SIP
Servers"). You may use the fully qualified domain name (FQDN) for a SIP serv-
er. If you add a colon with the port number after the FQDN DNS, a resolution
will be used; otherwise, the system will try DNS NAPTR and DNS SRV first.
You can force the SIP connection to use TCP by supplying an outbound proxy.
sip:hostname:5060;transport=tcp
Example:
Important: The outbound proxy is an important setting. If an outbound proxy
is not used, then the system will assume that SIP requests on this trunk can
come from any location. This will make it difficult for the system to match in-
coming SIP requests. Unless you want to receive requests from any location on
the Internet, you should specify an outbound proxy.
12. CO (central office) Lines: CO-lines can serve multiple purposes on the sys-
tem. They allow you to channelize a trunk and can be used in a way similar to
the CO-lines of traditional TDM-based PBX systems. Although snom ONE
runs calls through SIP trunks over computer networks instead of connecting to
Chapter 4: Trunks 133