Envelope rewrite by sendmail?
cswiger at mac.com
Wed Jan 25 21:44:31 UTC 2017
On Jan 25, 2017, at 12:42 PM, Trond Endrestøl <Trond.Endrestol at fagskolen.gjovik.no> wrote:
> A mail messages arrives on the small SMTP server addressed to
> shorty at short.tld <mailto:shorty at short.tld>. Sendmail, though the aliases mechanism, forwards
> the message to long.name at some.incredible.long.domain.name.tld <mailto:long.name at some.incredible.long.domain.name.tld>.
> Antispam measures such as SPF will flag the small SMTP server as not
> allowed to send email on behalf of the originator.
Yes. You will need the admins of some.incredible.long.domain.name.tld <mailto:long.name at some.incredible.long.domain.name.tld>
to agree and whitelist your short.tld mailserver if you want it to be a trusted relay.
> Thus, prior to forwarding each message, the small SMTP server will
> need to masquerade as the originator and rewrite the envelope's from
> address to an address within the short.tld domain.
Try not do that, unless both domains belong to you and share a common namespace for
delivery including aliases. Otherwise, From header munging will break various things,
most commonly mailing lists and bounce handling processing.
More information about the freebsd-questions