Cannot connect to mysql through network while unix socket works

[Oscar]

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‰¦ºx†j×­˜úèDear all,

I have a mysql-4.0.12 server installed on RH 8, it works fine for months before 
I
find the server unavailable from the remote host on the same LAN. I am sure 
there
isn't any firewall between server and client. I ssh to the server and find the 
mysqld
is running and functional, because I can connect to it via unix socket!!!

Things not changed event restart the mysql service, so I have to reboot the 
server :(

Anybody here has the same experience, and how this happened?

Oscar Yen.