Problems sending emails

[litusbdn]

Good morning,
I have done a basic installation of Opensense in my office.
I encounter the problem that when I send mails through Outlook, if the mail has an attachment (attachments of less than 2 MB) Outlook will remain loading for 3-4 minutes and finally send the mail.
If the email does not contain attachments, it is sent instantly.
This problem occurs with multiple accounts (Exchange, Imap, and Pop3).

Without opnsense, everything works correctly.

Any idea what it can be?

[litusbdn]

to explain further here's my current setup...

Router -> Pfsense -> Client PC

if I use the above configuration, I would be able to send e-mails thru external SMTP.

But if I use this configuration...

Router -> ClientPC

There will be no issues sending e-mails.

[curglaff]

Hey, did you ever figure this out? I have the same issue but anything over 100kb just sits in the Outbox and never sends.

[Patrick M. Hausen]

MTU/MSS problem? What type of connection is your Internet line?

[curglaff]

Hi, thanks for your reply. I have tried various MTU settings based on other posts, both on opnsense and the router all to no avail. It's a VDSL line.