Hi, I'm using postfix-3.8.5 on fedora40 with pypolicyd-spf-3.0.4 and some senders are experiencing weird timeout issues when trying to send to us:
8/22/2024 2:08:25 PM - Server at SA1PR22MB4256.namprd22.prod.outlook.com returned '550 5.4.300 Message expired -> 451 4.4.400 Error communicating with frontend host or destination host. -> 421 4.4.2 Connection dropped due to ConnectionReset' 8/22/2024 1:37:14 PM - Server at 209.216.90.118 (209.216.111.118) returned '451 4.4.400 Error communicating with frontend host or destination host. -> 421 4.4.2 Connection dropped due to ConnectionReset' On or around that time (and many other times throughout the day) I see many attempts at connecting, but no other details on those connections: Aug 22 01:36:34 iceman policyd-spf[586425]: : prepend Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=40.107.102.133; helo=nam04-dm6-obe.outbound.protection.outlook.com; envelope-from=zoe.osb...@qwickrate.com; receiver=jerseyshorefcu.org Aug 22 01:41:48 xavier policyd-spf[712089]: : prepend Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=40.107.101.115; helo=nam04-mw2-obe.outbound.protection.outlook.com; envelope-from=jason.heinr...@qwickrate.com; receiver=jerseyshorefcu.org Could it somehow be related to Microsoft 365 servers? I'm also not even sure it's related to SPF. This also isn't the only sender having this problem. I've done my best to correlate the log entries to something usable and found this, although I don't understand what could be the source of the timeout? Aug 22 01:36:33 iceman postfix-199/smtpd[584336]: connect from mail-dm6nam04on2133.outbound.protection.outlook.com[40.107.102.133] Aug 22 01:36:34 iceman postfix-199/smtpd[584336]: A5C98100002D6: client=mail-dm6nam04on2133.outbound.protection.outlook.com[40.107.102.133] Aug 22 01:51:36 iceman postfix-199/smtpd[584336]: timeout after BDAT (3293244 bytes) from mail-dm6nam04on2133.outbound.protection.outlook.com[40.107.102.133] Aug 22 01:51:36 iceman postfix-199/smtpd[584336]: disconnect from mail-dm6nam04on2133.outbound.protection.outlook.com[40.107.102.133] ehlo=2 starttls=1 mail=1 rcpt=1 bdat=0/1 rset=1 commands=6/7 I'm seeing quite a large number of those "timeout after BDAT" entries in my logs, all of which are from different outbound.protection.outlook.com servers. Given the instructions in https://www.postfix.org/BDAT_README.html I've disabled BDAT support for now, hoping this will alleviate the problem until I can identify the cause. Thanks, Alex
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