Replying to emails and using an Alias or "Personality"

spoof the "from" field or create a POP mailbox?

[microcars]

I have several small websites I administer and I have several "aliases" on each one that are all forwarded to my primary email account (earthlink).

I've been using Eudora and the "Personality" function to either create or reply to emails so that, to the recepient, it appears to come FROM whatever website they sent the email to. However- I've always noticed that -in the headers- the X-SENDER address always says (unverified), but it has never seemed to cause me any problems.

In fact I've been trying to ween people off using my Earthlink address entirely as I'd like eventually go with a different provider, but today I sent an email to my MOM using one my "Personalities" (and it's the one I told her to use in her Yahoo Address Book) and it bounced back with this:

SMTP error from remote mailer after MAIL FROM:<****@*******.***>:
host sbcmx3.prodigy.net [207.115.57.15]: 550 5.0.0 Access denied

I re-sent the message using my primary earthlink address and it did not bounce.

So I guess my question is, has spam filtering gotten to the point where my "Personalities" will now get rejected?
I got a bounce back on this one, how many just go to the bit bucket?
Should I go set up separate Mailboxes on my host now for each name on each website I want to use?
Or was this just a random bounce?

[Essex_boy]

I use seperate mail boxes for all sites, a real pain in teh boondocks but so.