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We can also confirm this by looking at the DNS records that H2 knows about: H2# show hosts Here is a capture of the DNS answer from H2 captured on the DNS server:Ībove, you can see that it is sourced from 192.168.1.150 and the answer shows 192.168.1.101.īelow, we have the DNS answer captures on H2, after NAT:Ībove, we see that the source IP address got translated and the answer on the application layer got translated to 192.168.2.101. In the output above, we see that the IP addresses of the DNS server and H1 got translated, but it also shows us that the DNS resource record is translated from 192.168.1.01 to 192.168.2.101. This is the outside IP address of H1, not its real IP address. H2 gets an answer from the DNS server and pings IP address 192.168.2.101. Success rate is 100 percent (5/5), round-trip min/avg/max = 6/9/16 ms Sending 5, 100-byte ICMP Echos to 192.168.2.101, timeout is 2 seconds: Translating "h1.networklessons.local".domain server (192.168.2.150) Now we try a ping from H2 to the hostname of H1: H2# ping h1.networklessons.local Let’s enable a debug on R1 to see NAT in action: R1# debug ip nat Let’s see what happens when H2 does a DNS request. The DNS server is reachable from the outside with IP address 192.168.2.150.

I captured the answer of the DNS server, you can see it below:Īs you can see above, the answer shows IP address 192.168.1.01 in the application layer of this packet. We can see the address that it resolved with the show hosts command: H1# show hostsĬodes: UN - unknown, EX - expired, OK - OK, ? - revalidate H1 resolves the hostname through the DNS server and pings its own IP address.

Success rate is 100 percent (5/5), round-trip min/avg/max = 2/3/8 ms Sending 5, 100-byte ICMP Echos to 192.168.1.101, timeout is 2 seconds: Translating "h1.networklessons.local".domain server (192.168.1.150) Let’s start with a simple lookup from H1: H1# ping h1.networklessons.local The DNS server has one entry for H1, that’s it. DNS1 is reachable from the outside through 192.168.2.150.H1 is reachable from the outside through 192.168.2.101.H2 is a host somewhere outside of our network.