DNS Redirection - Revision history

Casey at 14:36, 16 September 2013

2013-09-16T14:36:10Z

Casey at 18:50, 20 June 2013

2013-06-20T18:50:50Z

Casey: Created page with "Suppose you are using your Cisco router as a DNS server, and you would like to have certain domains redirected to specific servers for their lookups. This would be useful for..."

2013-06-20T18:48:16Z

Created page with "Suppose you are using your Cisco router as a DNS server, and you would like to have certain domains redirected to specific servers for their lookups. This would be useful for..."

New page

Suppose you are using your Cisco router as a DNS server, and you would like to have certain domains redirected to specific servers for their lookups. This would be useful for a remote VPN site that needs to look up internal hostnames from other sites, but doesn't want to use the other site's DNS server for internet lookups.

This example works for any hosts in the ".local" domain (ie: myhost.local) and any PTR lookups for 192.168.x.x IPs. Note with this setup, you do not use the '''ip name-server x.x.x.x''' global command.

<PRE>
ip dns name-list 100 permit .*.local
ip dns name-list 100 permit .*.168.192.IN-ADDR.ARPA

ip dns view INTERNET
domain name-server 8.8.8.8
domain name-server 8.8.8.4

ip dns view INTERNAL
domain name-server 10.10.10.5

ip dns view-list DNS-SERVERS
view INTERNAL 10
restrict name-group 100
view INTERNET 100
</PRE>

When a host queries the DNS server, it checks to see if the query matches name-list 100. If it matches, it queries the INTERNAL group of servers. Otherwise, it queries the INTERNET group.

← Older revision		Revision as of 18:50, 20 June 2013
Line 1:		Line 1:
−	Suppose you are using your Cisco router as a DNS server, and you would like to have certain domains redirected to specific servers for their lookups. This would be useful for a remote VPN site that needs to look up internal hostnames from other sites, but doesn't want to use the other site's DNS server for internet lookups.	+	Suppose you are using your Cisco router as a DNS server, and you would like to have certain domains redirected to specific servers for their lookups. This would be useful for a remote VPN site that needs to look up internal hostnames from other sites, but doesn't want to use the other site's DNS server for internet lookups. You could also use this as a centralized way of banner blocking.

	This example works for any hosts in the ".local" domain (ie: myhost.local) and any PTR lookups for 192.168.x.x IPs. Note with this setup, you do not use the '''ip name-server x.x.x.x''' global command.		This example works for any hosts in the ".local" domain (ie: myhost.local) and any PTR lookups for 192.168.x.x IPs. Note with this setup, you do not use the '''ip name-server x.x.x.x''' global command.

@@ Line 7: / Line 7: @@
 ip dns name-list 100 permit .*.168.192.IN-ADDR.ARPA
-ip dns view INTERNET
+ip dns view default
   domain name-server  8.8.8.8
   domain name-server  8.8.8.4
@@ Line 17: / Line 17: @@
   view INTERNAL 10
    restrict name-group 100
-  view INTERNET 100
+  view default 100
 </PRE>
-When a host queries the DNS server, it checks to see if the query matches name-list 100.  If it matches, it queries the INTERNAL group of servers.  Otherwise, it queries the INTERNET group.
+When a host queries the DNS server, it checks to see if the query matches name-list 100.  If it matches, it queries the INTERNAL group of servers.  Otherwise, it queries the default group.  Note that "default" is actually a keyword.  It refers to the same set of nameservers that the router will use for lookups when executing commands (ie "ping www.google.ca").