Cisco TelePresence Administrator's Manual page 61

LDAP server
n
NTP server
n
External Manager server
n
Remote logging server
n
You are recommended to use an IP address or FQDN (Fully Qualified Domain Name) for all server
addresses.
Note that the FQDN of the VCS is the Local host name plus the Domain name.
Impact on SIP messaging
The Local host name and Domain name are also used to identify references to this VCS in SIP
messaging, where an endpoint has configured the VCS as its SIP proxy in the form of an FQDN (as opposed
to an IP address, which is not recommended).
In this case the VCS may, for example, reject an INVITE request if the FQDN configured on the endpoint
does not match the Local host name and Domain name configured on the VCS. (Note that this check
occurs because the SIP proxy FQDN is included in the route header of the SIP request sent by the endpoint
to the VCS.)
DNS requests
By default, DNS requests use a random port from within the system's normal ephemeral port range (40000-
49999).
If required, you can specify a custom port range instead by setting DNS requests port range to Use a
custom port range and then defining the DNS requests port range start and DNS requests port range
end fields. Note that setting a small source port range will increase your vulnerability to DNS spoofing
attacks.
DNS servers
You must specify at least one DNS server to be queried for address resolution if you want to either:
use FQDNs (Fully Qualified Domain Names) instead of IP addresses when specifying external addresses
n
(for example for LDAP and NTP servers, neighbor zones and peers), or
use features such as URI dialing
n
Default DNS servers
You can specify up to 5 default DNS servers.
The VCS only queries one server at a time; if that server is not available the VCS will try another server
n
from the list.
The order that the servers are specified is not significant; the VCS attempts to favor servers that were last
n
known to be available.
Per-domain DNS servers
In addition to the 5 default DNS servers, you can specify 5 additional explicit DNS servers for specified
domains. This can be useful in deployments where specific domain hierarchies need to be routed to their
explicit authorities.
Cisco VCS Administrator Guide (X7.2)
or ENUM dialing
Network and system settings
Page 61 of 498