On 18 Mar 2004 at 14:34, John Kemp wrote: > Sue, Check the little things first. Are the IP's correct. Are the netmasks > identical. If the answer is yes - are you running a firewall with the Port 7 > blocked. The ping command falls under the ICMP protocol. Port 7 should be > the echo port for ICMP. > > Bon Chance...John Port numbers are sub-selections within the UDP and TCP protocols. Within TCP, port 7 is allocated for an "echo" service, but this is rarely used and should, in fact, be disabled. (It turns out that leaving it enabled permits some easy/nasty ways to kill a machine.) The "ping" command uses a different protocol, ICMP, which doesn't use port numbers. ICMP uses type and subtype values; ping uses the "echo request" and "echo reply" types. It's certainly *possible* that a firewall is blocking this, but the only time I've ever heard of that on an individual machine software firewall, it was the XP built-in firewall (have we eliminated that in this case?), and it was only blocking pings to the default gateway -- in this case, that would mean that the ICS machine should still be able to ping the other.... David Gillett The NOSPIN Group provides a monthly newsletter with great tips, information and ideas: NOSPIN-L, The NOSPIN Magazine Visit our web site to signup: http://freepctech.com