Reverse DNS setup on GNS3

[Mantas Sti]

I was able to configure a Cisco router to be a DNS server but is there a way to get a reverse DNS configured on it? When pinging the router's IP address it should resolve the IP into a hostname.

[Francesco Molino]

Hi

Normally when you configure your router as dns server and adding hosts with ip host command, the ptr should be automatically done.

Is that what you're looking for?

[Deepak Kumar]

Hi, 

I hope your solution will be "ip host www.xxx.com X.X.X.X" command.

Regards,

Deepak Kumar

[Mantas Sti]

I am able to resolve ip addresses into names with the ''ip host'' command but I need it the other way around. Say if you were pinging an IP address it would show you the host name of it.

[Francesco Molino]

Can you share your config please?

not tested on GNS but on real router it works:

Config on router: ip host esxi 10.100.99.2

Result nslookup based on IP

$ nslookup 10.100.99.2
Server: 10.100.1.1
Address: 10.100.1.1#53

Non-authoritative answer:
2.99.100.10.in-addr.arpa name = esxi.

[Deepak Kumar]

Hi,

By default, Ping is not sending any DNS query, if you are trying to ping with IP address. 

If you want to check the hostname also then you have to use some switches as

Ping -a X.X.X.X 

So it will check the PTR record also. It is tested you can check the PTR.

Regards,

Deepak Kumar

[Mantas Sti]

I'm ping from a router to another router which is configured as a DNS server.

[Deepak Kumar · Accepted solution]

Then there is no option to check PTR record. It will only check the A record.

Regards,
Deepak Kumar