I have just configured the following GNS3 network using Cisco 3740 routers:
The 192.168.137.0/24 network is connected to my Microsoft Loopback Adapter (C1) which is sharing the internet with my PCs Ethernet Adapter. OSPF is running on all networks (all area 0). R1 originates the static default route to 192.168.137.1 into the LSDB. At the moment R3 and R1 can access the internet.
S1 is really just a Cisco 3740 with an NM-16ESW module to make it act like a switch.
I have configured SPAN on S1 (with the destination set to the interface connected to my Microsoft Adapter). I ma running wireshark on my PC. When I tell it to monitor my Microsoft Loopback Adapter I can see ping packets that I generate from R3 to R1.
Despite being very chuffed that I have got this all to work, I have also noticed that my Microsoft Loopback Adapter is, as you would expect, recieving multicast OSPF hello packets. If I want any of my devices in this topology that are not on the 192.168.137.0/24 range to talk to internet, I need to add a static route into my PCs routing table (e.g. route ADD 192.168.2.0 MASK 255.255.255.0 192.168.137.2).
Just out of curiousity, can I configure my PC to develop an OSPF neighbourship and learn routes dynamically? Or maybe there is another routing protocol I can use?
