I have a new exim4 server and I need to forward some addresses to a gmail address.

[email protected] --> [email protected]

I have created the router with driver = redirect and everything seems to work on exim side. This is the router:

  driver = redirect
  data = ${lookup{$sender_address}lsearch{/etc/exim4/sender_redirects}}

however Gmail is refusing all emails with this error:

Server returned '<gmail-smtp-in.l.google.com #5.0.0 smtp; 550-5.7.1 [xx.xx.xx.xx] Our system has detected that this message is likely suspicious due to the very low reputation of the sending IP address. To best protect our users from spam, the message has been blocked. Please visit https://support.google.com/mail/answer/188131 for more information

My IP address is just given from the provider, and it is new and seems not included in any blacklist. I have tried to check the support link and, as far as I understand, I have to be sure exim is not breaking the envelope. Is this exim configuration breaking the evenlope? Can I do something?

1 Answer 1


Welcome to the world of big email players in general, and Gmail in particular.

Gmail is blocking mail based on "reputation" in order to fight spam. That is, it only accepts mail from servers that are known to be well-behaved according to some metric they set unilaterally. It is nearly impossible for a single new server outside an established mail organization to build up the necessary reputation to be able to deliver mail to Gmail. (Other big mail service providers act similarly, although most not quite as recklessly.)

The recommended solution is to not even try to get accepted as a real mail server, but instead send your mail as a client would, via message submission to port 587 of your mail provider with SMTP AUTH using the credentials of your mail account.

By the way, this is not specific to Exim. The exact same thing would happen if you tried doing it with Postfix, Sendmail, or Microsoft Exchange.

  • The problem is that ... I'm the mail provider of myself :-) I'm handling my domain and I have a mail server, but for some specific addresses I have to forward to external email. I can understand the reputation of an IP but, then, with a fresh IP seems I'm starting under the minimum score! Do you think the SRS method can help somehow? I read something about it, but not yet tried in exim.
    – Tobia
    Mar 12, 2021 at 14:02
  • (a) You may want to avoid Gmail for that sort of thing. Most other mail providers aren't quite as high-handed in deciding which mails they'll let their users receive as just Gmail. (b) I don't see any application for SRS in your scenario. You don't forward mail you received from external sources to Gmail, do you? Mar 12, 2021 at 21:48
  • Yes, my server is the public MX server for myeximdomain.com domain but for some particular addresses I have not to deliver them locally but forward messages to a Gmail address. Isn't this a SRS scenario?
    – Tobia
    Mar 13, 2021 at 15:23
  • 1
    Ah, sorry, I didn't read your question properly. Yes, indeed, it is. Mar 13, 2021 at 22:44
  • I partially solved with SRS. Now the email is accepted by Gmail, but of course flagged as spam! This is a step forward. It is incredibile because SPF and DKIM is "passed" but Gmail still consided them spam.
    – Tobia
    Mar 14, 2021 at 8:47

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