what does this mean? anybody knows ?

...
Feb 19 21:59:50 www sendmail[14741]: gethostbyaddr(216.234.xxx.1) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(66.51.xxx.65) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(66.51.xxx.161) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(216.234.xxx.2) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(216.234.xxx.22) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(216.234.xxx.17) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(216.234.xxx.23) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(216.234.xxx.24) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(216.234.xxx.21) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(216.234.xxx.25) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(216.234.xxx.26) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(216.234.xxx.27) failed: 1
Feb 19 21:59:51 www sendmail[14741]: gethostbyaddr(216.234.xxx.29) failed: 1
Feb 19 21:59:52 www sendmail[14741]: gethostbyaddr(216.234.xxx.15) failed: 1
...


Is the server configuration not correct ?

i had this problem well still do but tim @ tera-byte said not to worry about it.

It cannot find names of each IPs beacause you didn't assign them PTR records(using dns bind).

Can you assign PTR records by tera-byte's dns administrator?

I didn't see that option yet. Hope they'll add it soon.