[Exim] entry in rejectlog

I have hundreds of entries in my rejectlog that look like:

----------------------------------------------------------------------------
--
2001-07-16 11:10:32 rejected HELO from [64.221.225.150]: syntactically
invalid argument(s): _[206.102.79.223]_by
----------------------------------------------------------------------------
--
2001-07-16 11:10:44 rejected HELO from [64.221.225.150]: syntactically
invalid argument(s): _[188.167.62.176]_by
----------------------------------------------------------------------------
--
2001-07-16 11:10:49 rejected HELO from [64.221.225.150]: syntactically
invalid argument(s): _[176.212.114.159]_by
----------------------------------------------------------------------------
--
2001-07-16 11:10:57 rejected HELO from [64.221.225.150]: syntactically
invalid argument(s): _[229.88.87.40]_by

Is this malicious in nature? Or a moron



Derrick MacPherson
derrick@???