Recipient Verification problem

Report bugs and workarounds
Post Reply
nicola.piazzi
Posts: 218
Joined: 23 Apr 2015 09:45

Recipient Verification problem

Post by nicola.piazzi » 05 Sep 2016 08:59

For users that have EFA between Exchange and Internet is very useful to enable postfix recipient verification

reject_unknown_recipient_domain, check_recipient_access hash:/etc/postfix/recipient_access, reject_unverified_recipient, check_policy_service inet:127.0.0.1:2501

When reject_unverified_recipient enabled postfix check Internal server making a RCPT TO while external server make RCPT TO to postfix and answer USER UNKNOWN if internal server answer so.

With Exchange 2016/2013 there is a problem, the FrontEnd connector doenst do this check, and bounce later :-(
Solution is to enable Exchange "Recipient Filter Agent"
With "Recipient Filter Agent" we have
Hub Transport that receive at port 2525 that check mailbox exixstence at RCPT TO level
Frontend Transport that receive at port 25 that check mailbox exixstence at DATA level

Obviously postfix doesnt simulate at data level but only at rcpt to level
So we need to create an Hub Transport on port 2525 and we need that EFA in /etc/postfix/transport specify port 2525
is possible ?

User avatar
shawniverson
Posts: 2610
Joined: 13 Jan 2014 23:30
Location: Rushville, Indiana, USA
Contact:

Re: Recipient Verification problem

Post by shawniverson » 05 Sep 2016 09:35

This is doable.

You will need to simply edit the transport file directly and then issue the following command.

i.e

Code: Select all

example.com smtp:[somehostip]:2525

Code: Select all

sudo postmap /etc/postfix/transport
Version 3.0.2.6 released! Update now to keep your eFa secure!

nicola.piazzi
Posts: 218
Joined: 23 Apr 2015 09:45

Re: Recipient Verification problem

Post by nicola.piazzi » 05 Sep 2016 09:45

Yes, but this will be overwritten by EFA-Configure I suppose ?

User avatar
shawniverson
Posts: 2610
Joined: 13 Jan 2014 23:30
Location: Rushville, Indiana, USA
Contact:

Re: Recipient Verification problem

Post by shawniverson » 05 Sep 2016 14:07

Hmm...not sure....

Nope :)
Version 3.0.2.6 released! Update now to keep your eFa secure!

nicola.piazzi
Posts: 218
Joined: 23 Apr 2015 09:45

Re: Recipient Verification problem

Post by nicola.piazzi » 06 Sep 2016 16:09

I tried but not work, i suppose that reject_unverified_recipient uses VRFY instead RCPT TO and Exchange 2016 doesnt have VRFY

Odon Garma
Posts: 21
Joined: 08 May 2017 14:10

Re: Recipient Verification problem

Post by Odon Garma » 05 Sep 2018 13:44

any solution to this problem yet?

Post Reply