Homework: Firewall/Ping request problem.

[[]V[]essenjah]

So, I have been taking a Cisco Security class in my program and we were working on a lab the other day. So, basically, we had PC-A running into R1 (router 1) through R2 (router 2) and into (R3) to PC-C.

All I did was erase the startup config, reload, then I configured the interfaces, set a default route between R1 to R2 and R3 to R2, then set up summary routes from R2 to R1 and R3.

I found that I could ping all the way from PC-C through R3, R2, and R1 to PC-C and get an echo-reply response, which was fine.

Then I tried to ping as instructed from PC-A to R1, and found that it could see itself and it's own default gateway, but could not ping the serial interface, leaving R1 to R2. We found that all routers could ping R1 and get a reply but PC-A couldn't get a reply from anything else other than it's gateway and itself.

I looked through the Windows Firewall with my professor but we couldn't see anything wrong with it. Ping was enabled for incoming packets, but I didn't see anything for outgoing. I did see that imcp packets were blocked for printer and file sharing, but to my knowledge, they should be....

Anyone ever have this problem before?