gethostbyaddr Error

[SoloCDM]

The following error occurs in /var/log/maillog:

sendmail[32602]: gethostbyaddr(204.118.157.122) failed: 1

Because I'm connected to an ISP, the last set of numbers (after
the last period) change with every ISP connection, so how can I
put a generic entry in DNS?  The host is either mail.aculink.net
or aculink.net . . . I just don't know which is more appropriate
or standardization.

Note: When you reply to this message, please include the mailing
      list address in Cc: and my email address in To:.

*********************************************************************
Signed,
SoloCDM