Cisco TelePresence Administrator's Manual page 63

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
The DNS requests port range start and DNS requests port range end fields define the lower and upper
source ports in the range used for sending DNS queries. Requests to DNS will choose a random port from
this range. The default range is 1024 to 65535.
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.
For each additional per-domain DNS server address you can specify up to 2 Domain names. Any DNS
queries under those domains are forwarded to the specified DNS server instead of the default DNS servers.
Cisco VCS Administrator Guide (X7.1)
or ENUM dialing
Network and system settings
Page 63 of 479