S. Dobbs wrote on 12/05/2008 01:15:09 PM:

> My company uses Lotus Notes. When I send messages to internal
> Internet addresses that are within our DMZ, e-mail goes fine.
> Addresses that use an external domain return error messages. Each of
> these 3 are a little different.
>
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>   Error transferring to relay.VERIZON.NET; SMTP Protocol Returned a
> Permanent Error 550 5.1.8 invalid/host-not-in-DNS return address not
allowed

Yep, you need a DNS record for listserv.herc.com.  Talk to your DNS guru.

wbrown@wbrown:~$ host listserv.herc.com
Host listserv.herc.com not found: 3(NXDOMAIN)

> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> DELIVERY FAILURE: Error transferring to mx2.COMCAST.NET; SMTP
> Protocol Returned a Permanent Error               Subject:
> Your message
>   Subject: [HERCULES] Travel Expense Reports
>
> was not delivered to:
>   [log in to unmask]
>
> because:
>   Error transferring to mx2.COMCAST.NET; SMTP Protocol Returned a
> Permanent Error

This one is kind of stupid because it returned no details,

> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> DELIVERY FAILURE: Error transferring to mail.ASHLAND.COM; SMTP
> Protocol Returned a Permanent Error 553 5.1.8 <[log in to unmask]>...
> Domain of sender address [log in to unmask] does not
> exist               Subject:

>  . Domain of sender address [log in to unmask] does not
exist
>  Protocol Returned a Permanent Error 553 5.1.8 <[log in to unmask]>..
>  . Domain of sender address [log in to unmask] does not
exist


Yep.  What it says it what the problem is.  See first entry.

While Lotus Domino will work as a relay for listserv, it's a bit wonky.
Been there, done that, got lots of vendor-ware t-shirts.  If you can, find
a *nix base server to use as a mail relay.  If not, set one up.  It's
pretty easy these days.