STMP problems with pfsense/vlan/synology

gck303 · February 29, 2024, 12:12pm

I have just migrated from an iRedMail email server to use a Synology MailPlus service. The migration has gone fine.

But email attachments cannot be sent via an STMP service from a different VLAN. The problem is the same when sending from outlook, or a wordpress/php, or a proxmox mail gateway. Emails without attachments send fine, but email with attachments fail.

This problem does not occur when the synology is in the same VLAN as the sending machine.

All the MTUs are set to 1500.

I am totally stuck and out of ideas. Can anyone suggest anything to try next?

Thanks, George

Paul · February 29, 2024, 12:34pm

Can you setup smtp logs, to see what is going on.

gck303 · February 29, 2024, 1:02pm

Do you mean from the synology smtp service on teh server? I have found something from the outlook client…

I have edited the actual domain out of the logs.

2024.02.29 13:09:19 SMTP (mail.privatedomain.com): Authorizing to server
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): [tx] AUTH LOGIN
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): <rx> 334 VXNlcm5hbWU6
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): [tx] Z2NrQGNhbWxleXBob3RvZ3JhcGhpYy5jb20=
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): <rx> 334 UGFzc3dvcmQ6
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): [tx] *****
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): <rx> 235 2.7.0 Authentication successful
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): Authorized to host
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): Connected to host
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): [tx] MAIL FROM: <*****>
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): <rx> 250 2.1.0 Ok
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): [tx] RCPT TO: <*****>
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): <rx> 250 2.1.5 Ok
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): [tx] DATA
2024.02.29 13:09:19 SMTP (mail.privatedomain.com): <rx> 354 End data with <CR><LF>.<CR><LF>
2024.02.29 13:09:38 SMTP (mail.privatedomain.com): Connected to host
2024.02.29 13:09:38 SMTP (mail.privatedomain.com): Disconnected from host
2024.02.29 13:09:38 SMTP (mail.privatedomain.com): End execution
2024.02.29 13:09:38 gck@privatedomain.com: ReportStatus: RSF_COMPLETED, hr = 0x800ccc0f
2024.02.29 13:09:38 gck@privatedomain.com: Synch operation completed
2024.02.29 13:10:10 gck@privatedomain.com: Synch operation started (flags = 00000001)
2024.02.29 13:10:10 gck@privatedomain.com: UploadItems: 2 messages to send
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): Begin execution
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): Port: 465, Secure: SSL, SPA: no
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): Finding host
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): Securing connection
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): Connected to host
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 220 mail.privatedomain.com ESMTP Postfix
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): [tx] EHLO gck3060
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250-mail.privatedomain.com
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250-PIPELINING
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250-SIZE 10485760
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250-ETRN
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250-AUTH PLAIN LOGIN
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250-AUTH=PLAIN LOGIN
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250-ENHANCEDSTATUSCODES
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250-8BITMIME
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250-DSN
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250-SMTPUTF8
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250 CHUNKING
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): Authorizing to server
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): [tx] AUTH LOGIN
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 334 VXNlcm5hbWU6
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): [tx] Z2NrQGNhbWxleXBob3RvZ3JhcGhpYy5jb20=
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 334 UGFzc3dvcmQ6
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): [tx] *****
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 235 2.7.0 Authentication successful
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): Authorized to host
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): Connected to host
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): [tx] MAIL FROM: <*****>
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250 2.1.0 Ok
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): [tx] RCPT TO: <*****>
2024.02.29 13:10:10 SMTP (mail.privatedomain.com): <rx> 250 2.1.5 Ok

xMAXIMUSx · February 29, 2024, 1:50pm

What do you have for you attachment size in you settings?

gck303 · February 29, 2024, 2:02pm

The attachment in only a few kb. I do not think that it is related to the max attachment size as when I change the network the emails sends okay!

gck303 · March 12, 2024, 6:25pm

I found this issue!!!

I had to check the box with “enable multiple gateways” under “advanced settings” on the synology network settings.