I am using Redhat 6.1 with latest RPM updates to 4/Jan/2000 Approximately every 4 days linux stops responding. This has happened 3 times. I cannot telnet to it, ftp to it. It's DNS, DHCPD, SAMBA no longer work. I cannot logon locally, I enter my name "dion" and hit enter, I'm taken down to the next line, but the password prompt does not appear. I can however still ping the network card (192.168.0.1) from another PC. My only option is to press reset, CTL-ALT-DEL do not work, neither does ALT-F2 etc.. to get another console.
This is a misconfiguration problem - most likely a miscofigfured DNS server and a DNS query that takes a long time to time out. I suggest to boot into single user mode and check your DNS configuration.