No reply to ICMP /ping

[Misterk2001]

Hi there,
I'm currently experiencing a strange issue with my MAC book pro Snow Leopard.

My MAC won't reply back to ping commands issued on other hosts within the same network.

From IP stand point of view all is good all the hosts are within the same subnet 192.168.1.0/ 255.255.255.240.

I was pinging from two other machines the MAC's IP address and no reply back at all. When pinging from my MAC the other hosts, I get the ICMP replies I have switched off the firewall, and also while the firewall was on I have unchecked the stealth mode, no results.

I've created a new location and no ICMP replies when pinging MAC 's ip address from the other machines within the network.

In attempt to isolate the issue I directly connected the MAC with another computer via a crossover cable, and got the same symptoms

Is it there a UNIX command that will reset the TCP IP socket. ICMP is part of the TCP IP stack and reinstalling or resetting the socket should fix the problem...I guess ) Or is there a command in UNIX that can force deactivating the firewall.

Reinstalling the whole OS or deleting the system preferences settings is like using a hammer in stead of scalpel.

Thank you in advance for your advice and patience.

 

[balamw]

More details.

What are the other machines? Do they have a firewall that could be getting in the way?

B

 

[Misterk2001]

The other machines are: Win XP pro and win xp home.
Forgot to mention that I have no issues pinging between XP machines.
There is another device a Catalyst 3550 switch and have no problems pinging this device from MAC and other windows machines.Also have no problem pinging the other machines form the cat 3550 except the MAC which won't reply to ping. Checked the mac address table on the cat 3550 has learned all the host's mac within the network. The other devices are out o questions.the only machine that needs some work is the MAC.

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The only firewall that could possibly stop replies is the MAC's firewall which is not probably working or the ICMP protocol part of the TCP IP stock and it's probably corrupted. At least this is my point of view, but i;m open of any suggestions.

There are no other firewalls in the network, and as i mentioned in my first post did the same test by directly connecting the MAC to a Windows machines vie an Ethernet crossover cable and mac won't reply to ping .