Fax Attachment Size Error - Rejected over 10 MB

[Logicwrath]

One of our auto dealers is having trouble faxing using email to fax.  The 2600 MTA fax.zswitch.net is rejecting their faxes because of attachment size.

These attachments are typically between 10-15 megabytes.  Ideally we need the system to accept larger attachments like 25-50 megabytes.  However, I would consider 25 megabytes the minimum.

It appears that your rejecting all faxes over 10 megabytes.  Additionally, when I read the SMTP message the estimate message length seems to be larger than the attachment + a simple email.

Example:

This email has an 11 MB PDF.

Action: failed
Final-Recipient: sanitized-by-me.fax.zswitch.net
Status: 5.0.0
Remote-MTA: dns; fax.zswitch.net
Diagnostic-Code: smtp; 552 Estimated message length 15949478 exceeds limit of 10485670

When I convert 15949478 to bytes to megabytes it appears to be a 15 MB email.  However, the attachment is only 11 MB, and the simple email is not worth 4 MB.

Can we please remove the attachment size limit as soon as possible?  10 MB is far too small, we need at least 25 MB and would prefer 50 MB.

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Also, understand that breaking the PDF into smaller attachments is a problem, when you are faxing a credit company where the single fax number will send the fax randomly to different agents.  So if they send 2 faxes, one might go to one agent, and the other might go to another and this creates huge problems.

[Karl Stallknecht]

We asked 2600hz to increase the limit previously and they said they did not plan to increase it. They told us to just lower the resolution on the PDFs.

As for the difference in quota calculation, the following is from 2600hz support from a previous inquiry we made about this. Maybe it's related?

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Strange find. Email clients (on your side) have two ways to say "hi" to our mail server, HELO (older version) and EHLO (enhanced HELO).

Most of our testing was with clients who do EHLO. Your client did the older HELO. There was a difference in file size between the two. We've now made the two match so the file size limit is the same.

Please retry.

From engineering: "fax_smtp was running with different defaults for HELO and EHLO. HELO was restricted to 640kb. Microsoft exchange/smtp usually uses HELO instead of the more common EHLO."

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[Logicwrath]

Lowering the resolution of the PDF's will likely further reduce the quality of the PDF's.  The quality is already poor compared to other digital faxing services.

I would like to see the limit raised,  25MB is not unreasonable at all.  In my opinion 10MB is unreasonable.  What is the purpose of such a low limit?

Can we get an official comment?  I need to take action, and I am currently waiting for an official response.

[Karl Stallknecht]

For the record, I agree with you on all points :-)

[Isaac]

Hello,

Thank you for the comment/suggestion regarding the attachment size limits.  We will take this under advisement.