At 10:23 AM 11/11/99 -0600, Lyno Sullivan wrote:
At 08:44 AM 11/10/99 -0800, aphro wrote: >On Tue, 9 Nov 1999, Art Lemasters wrote: > >alemas > Which port number does ping use in Debian Linux? > >I do not believe ICMP uses ports, there are TYPES of ICMP though, the >'ping' command uses ICMP type 8. at least thats what i have blocked in my >firewall, it refuses pings but accepts traceroutes. According to "Building Internet Firewalls" ICMP,8 for incoming and outgoing ping requests ICMP,0 for responses to ping request
I think the "Building Internet Firewalls" is wrong. ICMP uses -types-, in other words the host sends an ICMP packet with type 'n' or recieves an ICMP packet with type 'n'. ICMP type 8 is an echo-request (ping). ICMP type 0 is an echo-reply (pong). The "incoming and outgoing" remark doesn't apply. Same with other types.
tracert uses: UDP ports >32768 (usually) for incming and outgoing probe ICMP,11 for incoming and outgoing "TTL exceeded' ICMP,3 for incoming and outgoing "servive unavailable"
Regards, Onno