Nortel NN46110-600 User Manual page 79

Companies often set up their own domain name system internally, and leave it to
the ISP to handle all external DNS. These companies have their own DNS servers,
but use the external DNS servers for non-company names. This splits the DNS
names into two separate systems: the private, company-controlled DNS names
and the Internet DNS names.
The VPN Router provides the following DNS services:
• DNS Proxy where the VPN Router caches information from corporate DNS
for faster address resolution. This eliminates the need for a separate branch
office server. See
DNS servers" on page
• Split Proxy DNS occurs when a negative response from a DNS server
(private) prompts the VPN Router to try a second DNS server (Internet). Split
DNS supports private and Internet names without mixing the two and
eliminates the need to publish private names on public DNS. See
"Configuring DHCP servers" on page 57
page 68.
You can configure the VPN Router 1010, 1050, or 1100 as a DNS proxy, which
means that it can act like a DNS server for any PC on the private network. The
PCs are configured to send their DNS queries to the DNS proxy, which in turn
passes the query to its set of true DNS servers. Whether you configured DHCP
client or PPPoE determines which DNS servers respond. When the DNS proxy
receives a DNS query from a PC, it passes the query on to the DNS servers until it
receives a response, which is subsequently returned to the PC.
You can configure up to four DNS servers. The ISP can assign more than one
DNS server, which are displayed on the window, but cannot be changed. Enable
split DNS if your DNS name space is split into private names and public names; a
DNS server knows the private names while another server knows the public
Internet DNS names.
To configure a DNS server:
Select System > Identity.
1
2 Enable DNS Proxy if you want the DNS Proxy to act as a DNS server to the
private side. It resolves names for locally connected hosts and those from
other DNS zones. It it enabled by default.
Nortel VPN Router Security — Servers, Authentication, and Certificates
"Configuring DHCP servers" on page 57
68.
Chapter 2 Configuring servers 69
and
and "Configuring DNS servers" on
"Configuring