actionmailer issues...any experts?

I have a rails app that can send emails to gmail, yahoo accounts. But
when it comes to more obscure accounts like emailme@my-app.com or
emailme@blah.edu, the mail never arrives even though the log shows
that
the email was sent. Any ideas why this may be happening?

I have sent an email directly through the same web server through the
command line using

mail -s and that worked. Why doesn't it work through my rails app?

here are my configuration settings (mostly default)

# Disable delivery errors, bad email addresses will be ignored
  config.action_mailer.delivery_method = :smtp
  config.action_mailer.raise_delivery_errors = true
  config.action_mailer.perform_deliveries = true
  config.action_mailer.default_charset = "utf-8"

config.action_mailer.smtp_settings = {
    :address => "localhost",
    :port => 25,
    :domain => "my-app.com"
  }

help please!

thanks
Tony

I have a rails app that can send emails to gmail, yahoo accounts. But
when it comes to more obscure accounts like emailme@my-app.com or
emailme@blah.edu, the mail never arrives even though the log shows
that
the email was sent. Any ideas why this may be happening?

Different hosts might be more or less restrictive when it comes to
spam (eg blacklists of ip ranges, whether they check SPF records etc...)

I have sent an email directly through the same web server through the
command line using

mail -s and that worked. Why doesn't it work through my rails app?

I know nothing about mail -s. Does it send email through the same smtp
server as your rails app. Would it set the same return-path/from
address (which is what matters for SPF) as your rails app ?

Fred

What does SPF mean? No when I use mail -s, the email is sent from
user@ip.address

What does SPF mean? No when I use mail -s, the email is sent from
u...@ip.address

When you send an email from foo@bar.com the mail server on the other
end can lookup the SPF record for the domain bar.com (this info is
part of the DNS records for bar.com). In a nutshell the SPF records
are used to determine whether the server sending mail from
something@bar.com is allowed to send mail on behalf of that domain.
Different mail servers receiving mail may be more or less stringent:
it could merely count towards a score that determines whether the
message is classed as spam or might lead to it being rejected
altogether.

Fred