Ok,
I installed Redhat 7.1 as a server on my comp and i am running a cable modem to give my friends permission to download mp3s from my comp. I also have apache 2.0 installed on it. Anyways, i scanned the ports on my comp and it found Host IP: XX.XX.XXX.XX No host name, Port N/A, Protocol ICMP, and No description is available. does anybody know what this mean? Also when i scanned with the UDP Scanner it found something on port 1, and the description is TCP-MUX-TCP Port Service Multiplexer. and then when i sacnned it it said Port 2 compressnet - management utility. Everytime i stop scanning and then start again, the port number increases by 1 and it gives different descriptions. Now it says Port 44-MPM-Flags-MPM FLAGS Protocol. is there anyway to stop people from pinging my ip? Thanks everyone.

What scanning software you using ?
What firewall software you running ?

Forget scanning your own box, look at what the system says it's got running, scans can miss stuff due to TCP/UDP timings.
type :
# netstat -nap

On your other question:
Whatever your using to scan the ports is not sending a known protocol like TCP is Protocol 6, ICMP is 1 etc etc etc but your scanner is sending a private protocol not in the 0-255 range.

So what happens is the Service Multiplexer replies with protocols 1-255 on port 1 and tries to connect it to the correct protocol, which it can't work out so it tries the next protocol. just a guess

Yes you can stop people pinging you by rejecting ICMP type 8 messages "and type 10, 15, 13 & 17"

/Raz

don't stop w/just a portscan... netstat and fuser are also your friends