DNS

The DNS container, connected to every AS and only accessibly by the instructors, runs a bind9 DNS server. In the l3_routers.txt configuration file, we can see that the DNS container is connected to every BELL router. The DNS server has the IP address 198.0.0.100/24 and as soon as the students have configured intra-domain routing and have advertised this subnet into OSPF, they should be able to reach the DNS server and use it.

For instance, a traceroute from LAUS-host to CHUR-host returns the following output:

root@LAUS ~> traceroute 3.107.0.1
traceroute to 3.107.0.1 (3.107.0.1), 30 hops max, 60 byte packets
 1  laus.group3 (3.108.0.2)  0.066 ms  0.012 ms  0.010 ms
 2  base.group3 (3.0.10.1)  10.115 ms  10.091 ms  10.078 ms
 3  zuri.group3 (3.0.9.1)  20.179 ms  20.166 ms  20.155 ms
 4  chur.group3 (3.0.7.2)  30.295 ms  30.285 ms  30.276 ms
 5  host.chur.group3 (3.107.0.1)  30.266 ms  30.257 ms  30.244 ms

The naming convention is quite straightforward: XXXX-YYYY.groupZ: where XXXX is the router or host which (should) have the shown IP configured on one of its interfaces; YYYY is the name of the router on the other end of the link connected to this interface (or "host" if it is a host); finally Z is the AS number. The IP addresses used on the links connecting two ASes (e.g., 179.x.x.x) are not translated.