I'm having a frustrating problem with one of our clients who is running an exchange SMTP server.
I have an emailing component that is written in .net and I've specifically used Mono DLL's to ensure that the email component sends the ELO and QUIT command for each message it sends.
Each mail I send will never exceed 10MB's including attachments, which is lower than the session size value set in the clients exchange configuration.
Still the problem persists. Any ideas where to look?