Xserve running Leopard Server

My colleague is experiencing an odd problem with a Leopard server… I also have seen a somewhat similar problem on another Leopard server… wondering if anyone has any ideas:

My colleague’s explanation of the problem bellow:

“Periodically, all services will lose the ability to authenticate new connections until the server is rebooted. When I check the logs, I’ll see something along these lines repeated over and over.

Aug 25 08:23:28 nameserver org.apache.httpd[81549]: httpd: bad user name www
Aug 25 08:23:28 nameserver com.apple.launchd[1] (org.apache.httpd[81549]): Exited with exit code: 1
Aug 25 08:23:28 nameerver com.apple.launchd[1] (org.apache.httpd): Throttling respawn: Will start in 10 seconds
Aug 25 08:23:31 nameserver mds[54]: (Error) Import: importer:0x8d7a00 Importer start failed for 501 (kr:268435459 (ipc/send) invalid destination port)
Aug 25 08:23:32 nameserver com.apple.launchd[1] (com.apple.installdb.system[81550]): getpwnam(“_installer”) failed
Aug 25 08:23:32 nameserver com.apple.launchd[1] (com.apple.installdb.system[81550]): Exited with exit code: 1
Aug 25 08:23:32 nameserver com.apple.launchd[1] (com.apple.installdb.system): Throttling respawn: Will start in 10 seconds
Aug 25 08:23:35 nameserver mds[54]: (Error) Import: importer:0x8d7a00 Importer start failed for 501 (kr:268435459 (ipc/send) invalid destination port)

I closed the SSH port and disabled root the last time this happened, but it doesn’t seem to help. httpd suggests the web service, which they are using to host a shared iCal calendar. Closing off port 80 in the firewall would cut out their remote users from getting iCal updates. Does anyone have an idea what’s going on, if this is some kind of attack, and what can be done about it?”