I'm trying to send e-mail from my machine to my internet mail address (using a php script or just in pine). I was getting this error message:

----- The following addresses had permanent fatal errors -----
<my_real_address@hero.com>
(reason: 553 5.1.8 <apache@uranium.hero.com>... Domain of sender address apache@uranium.hero.com does
not exist)

..because uranium.hero.com is not a real name in anyone's DNS - it's just what I call my computer.

So I tried setting up a masquerade through webmin to "hero.com" which is an actual machine name (and also where my internet mail account resides), but now I'm not getting any sort of bounce back and no mail in my internet account, however, my mail log now shows this:

Feb 8 00:59:03 uranium sendmail[31497]: k188x2Aq031497: from=apache, size=1226, class=0, nrcpts=1, msgid=< TheSystem@my_ip_address>, relay=apache@localhost
Feb 8 00:59:03 uranium sendmail[31499]: k188x3BQ031499: from=<apache@uranium.hero.com>, size=1339, class=0, nrcpts=1, msgid=< TheSystem@my_ip_address>, proto=ESMTP, daemon=MTA, relay=localhost.localdomain [127.0.0.1]
Feb 8 00:59:03 uranium sendmail[31497]: k188x2Aq031497: to=my_real_address@hero.com, ctladdr=apache (48/48), delay=00:00:01, xdelay=00:00:00, mailer=relay, pri=30372, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (k188x3BQ031499 Message accepted for delivery)
Feb 8 00:59:03 uranium sendmail[31501]: k188x3BQ031499: to=<my_real_address@hero.com>, ctladdr=<apache@uranium.hero.com> (48/48), delay=00:00:00, xdelay=00:00:00, mailer=esmtp, pri=30485, relay=hero.com. [207.151.19.45], dsn=5.6.0, stat=Data format error
Feb 8 00:59:03 uranium sendmail[31501]: k188x3BQ031499: k188x3BQ031501: DSN: Data format error
Feb 8 00:59:03 uranium sendmail[31501]: k188x3BQ031501: to=root, delay=00:00:00, xdelay=00:00:00, mailer=local, pri=32363, dsn=2.0.0, stat=Sent


My host (hero.com) does not allow other people to use its SMTP server, so I can't relay through it. Is there a moderately easy solution for an e-mail neophyte like myself?

FYI: I just chose "uranium.hero.com" as a FQDN - my machine and hero.com are not related in any way.

do you have uranium.hero.com in your /etc/hosts?

yes

If you have an external email address then you can set this
up as a relay address. Also masquerade all external email
as coming from this address. Disable DNS lookup since many
email servers don't reply to this request.