2. The associated target zones are queried, in rule priority order, for the URI.
l
If one of the target zones is a DNS zone, the VCS attempts to locate the endpoint through a DNS
lookup. It does this by querying the DNS server configured on the VCS for the location of the domain as
per the
URI resolution process via DNS
. If the domain part of the URI address is resolved successfully
the request is forwarded to those addresses.
l
If one of the target zones is a neighbor, traversal client or traversal server zones, those zones are
queried for the URI. If that system supports URI dialing via DNS, it may route the call itself.
Adding and configuring DNS zones
To enable URI dialing via DNS, you must configure at least one DNS zone. To do this:
1. Go to
Configuration > Zones > Zones
.
2. Click
New
. You are taken to the
Create zone
page.
3. Enter a
Name
for the zone and select a
Type
of
DNS
.
4. Configure the DNS zone settings as follows:
Field
Guidelines
Hop
count
When dialing by URI via DNS, the hop count used is that configured for the DNS zone associated
with the search rule that matches the URI address (if this is lower than the hop count currently
assigned to the call).
If URI address isn't matched to a DNS zone, the query may be forwarded to a neighbor. In this
case, the hop count used will be that configured for the neighbor zone (if this is lower than the hop
count currently assigned to the call).
H.323
and
SIP
modes
The H.323 and SIP sections allow you to filter calls to systems and endpoints located via this zone,
based on whether the call is located using SIP or H.323 SRV lookups.
Include
address
record
This setting determines whether, if no NAPTR (SIP) or SRV (SIP and H.323) records have been
found for the dialed alias via this zone, the VCS will then query for A and AAAA DNS records
before moving on to query lower priority zones.
You are recommended to use the default setting of
Off
, meaning that the VCS will not query for A
and AAAA records, and instead will continue with the search, querying the remaining lower priority
zones. This is because, unlike for NAPTR and SRV records, there is no guarantee that the A/AAAA
records will point to a system capable of processing the relevant SIP or H.323 messages (LRQs,
Setups, etc.) - the system may instead be a web server that processes http messages, or a mail
server that processes mail messages. If this setting is
On
, when a system is found using A/AAAA
lookup, the VCS will send the signaling to that destination and will not continue the search
process. If the system does not support SIP or H.323, the call will fail.
Zone
profile
For most deployments, this option should be left as
Default
.
5. Click
Create zone
.
Configuring search rules for DNS zones
If you want your local VCS to use DNS to locate endpoints outside your network, you must:
n
configure the DNS servers
used by the VCS for DNS queries
n
create a DNS zone and set up associated search rules that use the
Pattern string
and
Pattern type
fields
to define the aliases that will trigger a DNS query
Cisco VCS Administrator Guide (X8.1.1)
Page 206 of 507
Dial plan and call processing
About URI dialing
