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How a router can resolve dns without ip name-server command?

godspeeds
Level 1
Level 1

Hello everyone,

A question about the command "ip name-server *.*.*.*"

If I didn't put in the DNS server, the router can still resolve the domain name. You can see the domain server is 255.255.255.255.

Why does this happens?

R4#ping www.cisco.com

Translating "www.cisco.com"...domain server (255.255.255.255) [OK]

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 184.31.192.170, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

R4#

3 Replies 3

godspeeds
Level 1
Level 1

Resolved.

There is a DNS server in the local network. So it can receive the broadcast DNS request and reply with the right IP address.

Thanks Guys.

tjareen
Level 1
Level 1

Hi,

There is a name server inside the LAN. Before searhing in the DNS server, it checks the name server in the LAN to reduce the time for searching. The name server of the LAN is like a cache which stores the results coming from the DNS server.

So, it is name server of the LAN which is resolving the IP address.

Thank you.

* please rate the helpful posts.

tjareen
Level 1
Level 1

The name server is maintained by your ISP. Sorry I forgot to say this.