Cisco Cisco Expressway Maintenance Manual
Dialing by IP address
Dialing by IP address is necessary when the destination endpoint is not registered with any system.
Calls to unknown IP addresses
Although the Expressway supports dialing by IP address, it is sometimes undesirable for the Expressway to
be allowed to place a call directly to an IP address that is not local. Instead, you may want a neighbor to place
the call on behalf of the Expressway, or not allow such calls at all. The Calls to unknown IP addresses
setting (on the
be allowed to place a call directly to an IP address that is not local. Instead, you may want a neighbor to place
the call on behalf of the Expressway, or not allow such calls at all. The Calls to unknown IP addresses
setting (on the
addresses which are not on its local network, or registered with one of its neighbors:
n
Direct: the Expressway attempts to place the call directly to the unknown IP address without querying any
neighbors.
neighbors.
n
Indirect: the Expressway forwards the search request to its neighbors in accordance with its normal search
process, meaning any zones that are the target of search rules with an Any IP Address mode. If a match is
found and the neighbor’s configuration allows it to connect a call to that IP address, the Expressway will
pass the call to that neighbor for completion.
process, meaning any zones that are the target of search rules with an Any IP Address mode. If a match is
found and the neighbor’s configuration allows it to connect a call to that IP address, the Expressway will
pass the call to that neighbor for completion.
n
Off: the Expressway will not attempt to place the call, either directly or indirectly to any of its neighbors.
The default setting is Indirect.
This setting applies to the call's destination address prior to any zone transforms, but after any pre-search
transforms or Call Policy rules have been applied.
transforms or Call Policy rules have been applied.
Calling unregistered endpoints
An unregistered endpoint is any device that is not registered with an H.323 gatekeeper or SIP registrar.
Although most calls are made between endpoints that are registered with such systems, it is sometimes
necessary to place a call to an unregistered endpoint.
Although most calls are made between endpoints that are registered with such systems, it is sometimes
necessary to place a call to an unregistered endpoint.
There are two ways to call to an unregistered endpoint:
n
by dialing its URI (this requires that the local Expressway is configured to support URI dialing, and a DNS
record exists for that URI that resolves to the unregistered endpoint's IP address)
record exists for that URI that resolves to the unregistered endpoint's IP address)
n
by dialing its IP address
Recommended configuration for firewall traversal
When an Expressway-E is neighbored with an Expressway-C for firewall traversal, you should typically set
Calls to unknown IP addresses to Indirect on the Expressway-C and Direct on the Expressway-E.
Calls to unknown IP addresses to Indirect on the Expressway-C and Direct on the Expressway-E.
Cisco Expressway Administrator Guide (X8.5)
Page 168 of 394
Dial plan and call processing
Dialing by IP address