Simple: if from a local user, then....

How do I test if a message comes in from a user on my machine (ie no '@' in  
the 'from' line.)

Thanks

TjL

ps -- Hebrew started as of 2 July, and ends on 22 August, so
please understand if responses are slow.  I am taking a 2
semester class in 8 weeks for 6 credits

--
TjL <luomat(_at_)peak(_dot_)org>