Mailcow Sieve forwarding failure

Murugan

Hi Team,

We are facing an issue with Mailcow where Sieve-based forwarding fails with a temporary error.

Issue observed:
When mail forwarding is enabled from the Mailcow web UI (Settings→ Mail → Forward), We have tested by sending mails but we facing the following error.

Error:
Jan 30 13:55:55 77675c987993 postfix/lmtp[3877]: 1322AFD29C: to=abc@test.test, relay=dovecot[172.22.1.250]:24, delay=1232, delays=1232/0.03/0.01/0.02, dsn=4.2.0, status=deferred (host dovecot[172.22.1.250] said: 451 4.2.0 abc@test.test Execution of Sieve filters was aborted due to temporary failure (in reply to end of DATA command))

ETNyx

Sieve is part of Dovecot, so post corresponding Dovecot log, this is Postfix log. There should be some whit more information,…

Murugan

Hi, Below I have shared the Dovecot Logs

Jan 30 15:44:35 7ff92eee86dd dovecot: lmtp(abc@test.test)<29649><kKYCK4uEfGnRcwAAVSa2Tw>: Error: smtp-client: conn postfix:588 ([fd4d:6169:6c63:6f77::12]:588) [1]: connect(postfix:588) failed: Connection refused
Jan 30 15:44:35 7ff92eee86dd dovecot: lmtp(abc@test.test)<29649><kKYCK4uEfGnRcwAAVSa2Tw>: Error: sieve: msgid=<3c0a1-697c8480-43-65c81e80@100970194>: redirect action: failed to redirect message to test@test.test: smtp(postfix:588): RCPT TO failed: Failed to connect to remote server (temporary failure)
Jan 30 15:44:35 7ff92eee86dd dovecot: lmtp(abc@test.test)<29649><kKYCK4uEfGnRcwAAVSa2Tw>: Error: sieve: Execution of script /var/vmail/sieve/global_sieve_after.sieve was aborted due to temporary failure
Jan 30 15:44:35 7ff92eee86dd dovecot: lmtp(29649): Disconnect from 172.22.1.253: Logged out (state=READY)

ETNyx

Hmm nothing definitive, just any chance you wanted (setup) disabling of ipv6 in past?

Murugan

No, IPv6 was not intentionally disabled in our setup.

Is there any recommended alternative approaches to configure mail forwarding.

ETNyx

Check this https://community.mailcow.email/d/3211-dovecot-sieve-filters-failing

other than that try to test your sieve, sometimes it can fail on valid mail due to specific chars posted trough SoGo UI (if I recall this right,…), and I presume you obfuscate what you are doing right?

so sieve-test or sievec -d -D check docs,…

Murugan

Hi,

Thanks for the explanation.

To clarify our setup:
We have not manually created or customized any Sieve scripts.

The forwarding was configured only via the UI:

Mail account → Settings → Mail → Forward

We entered the external email address and saved it

No custom filters, conditions, or scripts were added

No Sieve rules were edited via CLI or SOGo

As checked, I think Dovecot tries to redirect emails using the redirect action, it attempts to connect to Postfix via IPv6, but the connection is refused. Is there any option to disable IPv6 and force it to connect through IPv4?

ETNyx

Yes, I can’t find it right now, but i think I saw case when user enter mail address somewhere into SoGo and even address was RFC complaint SoGo was not and things start to break. So I wanted you to make some kind of lint test over sieve filter to ensure it’s ok after all.

Murugan

Hi,

Thanks for the clarification, that helps.

To confirm, we have not manually created or edited any Sieve scripts and only enabled forwarding via the UI (Settings → Mail → Forward). We understand that SOGo might still generate Sieve rules internally.

Could you please advise how exactly we should validate or lint-test the UI-generated Sieve filters in a Mailcow setup?

Which Sieve file(s) should we check (user-level or global)?

Are there recommended commands or tools you suggest using in this case?

Apologies if this is basic — we just want to ensure we are checking the correct place in the correct way.

Thanks again for your guidance.

ETNyx

I would start /var/vmail/sieve/global_sieve_after.sieve, since it’s mentioned in logs and direct command:

docker compose exec dovecot-mailcow sievec -d /var/vmail/sieve/global_sieve_after.sieve
docker compose exec dovecot-mailcow sieve-test /var/vmail/sieve/global_sieve_after.sieve

I did not tested it! please check docs and make your own research,…

Also you can check user-level sieves too,…

Murugan

hanks for the guidance.

We followed your suggestion and started by checking the global Sieve scripts mentioned in the logs.

We ran the following commands inside the dovecot container:

sievec -d /var/vmail/sieve/global_sieve_after.sieve
sievec -d /var/vmail/sieve/global_sieve_before.sieve

sievec -d /var/vmail/sieve/global_sieve_after.sieve

Header:

version = 2.0
flags = 0×00000000

Script metadata (block: 0):

class = file
class.version = 0
location = /var/vmail/sieve/global_sieve_after.sieve

Required extensions (block: 1):

0: fileinto (id: 5)
1: mailbox (id: 21)
2: variables (id: 17)
3: subaddress (id: 10)
4: envelope (id: 7)
5: duplicate (id: 25)
Main program (block: 2):

Address Line Code
00000000: DEBUG BLOCK: 3
00000001: EXTENSIONS [6]:
00000002: fileinto
00000004: mailbox
00000006: variables
00000008: VARIABLES SCOPE [1] (end: 00000012)
0000000d: 0: ‘tag’
00000012: subaddress
00000014: envelope
00000016: duplicate
00000018: 11: HEADER
0000001b: match type: contains
0000001e: header names: STR[11] “X-Spam-Flag”
0000002c: key list: STR[3] “YES”
00000032: 11: JMPFALSE 12 [0000003f]
00000037: 12: FILEINTO
00000038: folder: STR[4] “Junk”
0000003f: 15: ENVELOPE
00000042: 16: address part: detail
00000045: match type: matches
00000048: envelope part: STR[2] “to”
0000004d: key list: STR[1] “*”
00000051: 16: JMPFALSE 109 [000000bf]
00000056: 17: HEADER
00000059: match type: contains
0000005c: header names: STR[9] “X-Moo-Tag”
00000068: key list: STR[3] “YES”
0000006e: 17: JMPFALSE 80 [000000bf]
00000073: 19: SET
00000075: variable: VAR[0] ${tag}
00000079: value: MATCHVAL 1
0000007d: modifier: lower
00000080: modifier: upperfirst
00000083: 20: MAILBOXEXISTS
00000084: mailbox-names: CAT-STR [2]:
00000086: STR[6] “INBOX/”
0000008f: MATCHVAL 1
00000092: 20: JMPFALSE 24 [000000ab]
00000097: 21: FILEINTO
00000098: folder: CAT-STR [2]:
0000009a: STR[6] “INBOX/”
000000a3: MATCHVAL 1
000000a6: 21: JMP 24 [000000bf]
000000ab: 23: FILEINTO
000000ae: SIDE-EFFECT: create
000000b0: folder: CAT-STR [2]:
000000b2: STR[6] “INBOX/”
000000bb: VAR[0] ${tag}
000000bf: 27: DUPLICATE
000000c0: 27: JMPFALSE 6 [000000c7]
000000c5: 28: DISCARD
000000c6: 29: STOP
000000c7: 29: [End of code]

sievec -d /var/vmail/sieve/global_sieve_before.sieve

Header:

version = 2.0
flags = 0×00000000

Script metadata (block: 0):

class = file
class.version = 0
location = /var/vmail/sieve/global_sieve_before.sieve

Required extensions (block: 1):

0: mailbox (id: 21)
1: fileinto (id: 5)
Main program (block: 2):

Address Line Code
00000000: DEBUG BLOCK: 3
00000001: EXTENSIONS [2]:
00000002: mailbox
00000004: fileinto
00000006: 6: HEADER
00000009: match type: contains
0000000c: header names: STR[12] “Chat-Version”
0000001b: key list: STR[0] ""
0000001e: 6: JMPFALSE 58 [00000059]
00000023: 7: MAILBOXEXISTS
00000024: mailbox-names: STR[9] “DeltaChat”
00000030: 7: JMPFALSE 22 [00000047]
00000035: 8: FILEINTO
00000036: folder: STR[9] “DeltaChat”
00000042: 8: JMP 21 [00000058]
00000047: 10: FILEINTO
0000004a: SIDE-EFFECT: create
0000004c: folder: STR[9] “DeltaChat”
00000058: 12: STOP
00000059: 12: [End of code]

ETNyx

No error there, you may try check users scripts

docker compose exec dovecot-mailcow sievec -d /var/vmail/domain.com/user/sieve/sogo.sieve

you my find it like

docker compose exec dovecot-mailcow find /var/vmail -name "*.sieve" -type f