Enhancement #3347

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Disable Postfix address_verify_negative_cache

Added by Davide Principi over 5 years ago. Updated over 5 years ago.

Status:CLOSEDStart date:
Priority:NormalDue date:
Assignee:-% Done:

100%

Category:nethserver-mail-common
Target version:v6.7
Resolution: NEEDINFO:No

Description

The "negative" address cache contains email addresses known to be non-existent.

The typical management problem is:
  • a message to non existent email address arrives
  • "non-existent" cache entry is recorded
  • the email address is created
  • the "non-existent" state is not updated

We could sacrifice some MTA performance to simplify the management, by disabling the negative cache.

Related issues

Related to NethServer 6 - Enhancement #3135: Postfix: in-memory address verification database CLOSED

Associated revisions

Revision 5c90a7a3
Added by Davide Principi over 5 years ago

Don't cache negative responses. Refs #3347

Revision dca8ccde
Added by Davide Principi over 5 years ago

Reduce cache lifetime for negative responses. Refs #3347

History

#1 Updated by Davide Principi over 5 years ago

  • Status changed from TRIAGED to MODIFIED
  • % Done changed from 20 to 60

Test case

  • configure mydomain.com on NethServer
  • send a message to a non-existent address : it must be refused
  • create the email address for the admin user
  • send the message again: it must be accepted immediately

#2 Updated by Davide Principi over 5 years ago

  • Status changed from MODIFIED to ON_QA
  • % Done changed from 60 to 70

In nethserver-testing:
nethserver-mail-common-1.5.2-1.1.g5c90a7a.ns6.noarch.rpm

#3 Updated by Davide Principi over 5 years ago

  • Related to Enhancement #3135: Postfix: in-memory address verification database added

#4 Updated by Davide Principi over 5 years ago

  • Status changed from ON_QA to TRIAGED
  • % Done changed from 70 to 20

Disabling the negative cache completely has some side effects that need to be considered carefully... We can reduce the cache entry lifetime to mitigate side effects.

#5 Updated by Davide Principi over 5 years ago

  • Status changed from TRIAGED to MODIFIED
  • Assignee set to Davide Principi
  • % Done changed from 20 to 60

#6 Updated by Davide Principi over 5 years ago

  • Status changed from MODIFIED to ON_QA
  • Assignee deleted (Davide Principi)
  • % Done changed from 60 to 70

In nethserver/testing
nethserver-mail-common-1.5.2-1.3.gdca8ccd.ns6.noarch.rpm

#7 Updated by dz0 0te over 5 years ago

  • Assignee set to dz0 0te

#8 Updated by Giacomo Sanchietti over 5 years ago

  • Assignee changed from dz0 0te to Giacomo Sanchietti

#9 Updated by Giacomo Sanchietti over 5 years ago

  • Status changed from ON_QA to VERIFIED
  • Assignee deleted (Giacomo Sanchietti)
  • % Done changed from 70 to 90

After upgrading the package, I tried to send to an email to non-existent users (SMTP connection must start from an external IP address):

Feb 17 17:44:10 test1 transfer/smtpd[23839]: connect from nocbackend.nethesis.it[95.138.187.145]
Feb 17 17:44:18 test1 transfer/smtpd[23839]: NOQUEUE: reject: RCPT from nocbackend.nethesis.it[95.138.187.145]: 550 5.1.1 <q@neth.eu>: Recipient address rejected: undeliverable address: host test1.neth.eu[/var/run/dovecot/lmtp] said: 550 5.1.1 <q@neth.eu> User doesn't exist: q@neth.eu (in reply to RCPT TO command); from=<filippo@neth.net> to=<q@neth.eu> proto=ESMTP helo=<ibm.com>
Feb 17 17:44:18 test1 postfix/cleanup[23841]: 2D2473F9ED: message-id=<20160217174418.2D2473F9ED@test1.neth.eu>
Feb 17 17:44:18 test1 postfix/qmgr[23285]: 2D2473F9ED: from=<double-bounce@test1.neth.eu>, size=228, nrcpt=1 (queue active)
Feb 17 17:44:18 test1 postfix/local[23842]: 2D2473F9ED: to=<giacomo@test1.neth.eu>, orig_to=<q@neth.eu>, relay=local, delay=0.03, delays=0.02/0.01/0/0, dsn=2.0.0, status=deliverable (aliased to giacomo)

I created the new mail address, I did another try: the destination address have been accepted after a couple of minutes.

#10 Updated by Giacomo Sanchietti over 5 years ago

  • Status changed from VERIFIED to CLOSED
  • % Done changed from 90 to 100

Released in 6.7/updates:
nethserver-mail-common-1.5.3-1.ns6.noarch.rpm

Released in 7.2.1511/updates:
nethserver-mail-common-1.5.3-1.6.g69695ec.ns7.noarch.rpm

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