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[Resolved] Is there a size limit for individual emails with attachments


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Posted

Hi one of our clients is complaining about emails they send to our domain getting rejected as too large? (Before we moved to SpamCop our ISP could handle individual emails with 20Mb attachments)

I've tried sending in an 8Mb email (sent from gmail also a 20mb limit) and I received this message

Technical details of permanent failure:

PERM_FAILURE: SMTP Error (state 16): 552 5.3.4 Error: message file too big

I'm pretty sure we have pop3ed 7mb emails out w/o issue.

I was wondering what the maximum size would be and if this has changed recently?

Many thanks,

James

Posted

JT set up this system as an e-mail server. No one is going to try to read a 20Meg e-mail. There are much more efficient ways to move files across the net.

Previous servers were configured with the Apache/PHP/etc. defaults of 2Meg file size limits.

Posted
<snip>

No one is going to try to read a 20Meg e-mail.

...Wazoo, you make it sound as if you don't use modern Microsoft applications or multimedia files. A 20 MB Word, PowerPoint or Excel attachment is only of modest size. If the attachment is a GIF or MPG, it's downright tiny. Heck, I've created a 2MB e-mail just copying a screenshot into an Outlook e-mail! :D <G>
Posted

JT set up this system as an e-mail server. No one is going to try to read a 20Meg e-mail. There are much more efficient ways to move files across the net.

Previous servers were configured with the Apache/PHP/etc. defaults of 2Meg file size limits.

Thanks for the quick reply :)

Attachments can be images and drawings etc., yes there are other ways of moving files and we have unlimited file uploads to our ftp servers, however what is far more important especially for non technical users sending these documents is point and click - poof gone!

With other methods they have to more specialist technical knowledge and often have to wait for the completion of the send on the their workstation whereas the time of transmission to the email sever on the LAN is almost instantaneous as the workload is handled/negotiated queued on the office SMTP server. Freeing the non technical user up to do more useful things ;)

Posted
one of our clients is complaining about emails they send to our domain getting rejected

Wait..."send to our domain" doesn't sound as if the messages are being sent to a SpamCop email account. Therefore, I'm guessing that perhaps the hosting server for your domain is trying to automatically forward these messages to a SpamCop email account? Or maybe you've set up your email account to try to POP the messages off your server? These details are important, and so your question needs some clarification.

DT

Posted

Update: no, there's no 2-meg limit for attachments on mesages sent to SC email accounts...I just ran some extensive tests. I tried sending a message with a 9.66 meg PDF attached (which, when encoded was about 13M), and finally succeeded, when using my Gmail account to do the sending. My first two attempts used other SMTP services, including the one provided by SpamCop, and they both (the servers being asked to relay the message for me...not the receiving server) responded with:

552 Message size exceeds fixed limit

But the attempt I made using Gmail worked just fine, so as I suspected the error provided by the OP is probably *not* coming from SpamCop's email server(s) but rather from some other point in the path...most likely involving the hosting of the "domain" mentioned.

Update: both of the SMTP servers mentioned above let me send a 2.75M (3.9M encoded/sent) attachment to my SpamCop email account. So the limiting factor seems to be *outside* of SpamCop. We can probably receive something as large as people can send.

DT

Posted

Just spent a long, long time re-reading all those previous Posts, Topics, and Discussions on problems with file attachments. Here's one significant change .... Composing an e-mail now via WebMail now shows;

(Maximum Attachment Size: 10,485,760 bytes)

So, assumedly with all the server upgrades along the line, this has been bumped up.

There is another Discussion that a user suggested that e-mail Forwarded to the SpamCop.net e-mail server, then POP'd from another system did allow for much larger files to pass. Personally, I don't really believe that, as in other Discussions (with some error messsages included) it would appear that these attachments are in fact stored as files, and these huge files in fact ran into the 2Meg file limit. The actual problem seemed to boil down that the e-mail server would 'accept' the huge file, but there was no way to 'receive/download/access' that file .... back to the 2Meg limit. More than likely, although the 'e-mail side of the system 'accepted that package, it ptobably ended up a but hosed when it came time to actually 'save' the file, thus creating 'problems' for the user then trying to 'read' that e-mail. However, it would seem that this has changed (based on the above notation) to 10Meg these days.

Posted

Thanks DavidT! Independent 3rd party tests are a great help - very much appreciated :)

The Emails are forwarded to SpamCop, I can not see any limits in DNS/Forwarding providers help pages so I have asked the same question of their technical support. We have been using them for quite some years and I know we have had larger emails in the past so perhaps something has changed with their forwarding software.

Many thanks,

James

Posted
From: "Wazoo"

To: "JT"

Cc: "trevorb"

Subject: e-mail limits

Date: Wed, 10 Oct 2007 19:29:59 -0500

http://forum.spamcop.net/forums/index.php?showtopic=8818

file-size limits came up again. I see that the WebMail Compose limit is now reading as 10Meg attachment size, whereas it was 2Meg last (multiple) times it came up.

So, to once again try to bring the FAQ up to date;

Account limits on storage space are ?????

File Attachment size received, handled, passed on by the WebMail is limited to what?

Is there any difference in limits based on the connection, i.e. POP3 versus IMAP versus Forwarding?

Posted

Wazoo - IIUC, this topic has nothing to do with a "webmail compose limit." That's an issue of *sending* mail from a SpamCop account, not *receiving*, so...?????

DT

Posted
Wazoo - IIUC, this topic has nothing to do with a "webmail compose limit." That's an issue of *sending* mail from a SpamCop account, not *receiving*, so...?????

I'm going with that the change in the 'compose' window has gone way up, so the server settings had to match to allow that to happen .... which would also feed into the 'rest of the story' .. as those changes would also feed into the saving/storage of e-mails/attachments.

Posted

But I've never had a 2 meg limit, Wazoo...I'm afraid you're clouding this issue more than helping. I hope Trevor drops by to read this whole thread.

DT

Posted
But I've never had a 2 meg limit, Wazoo...I'm afraid you're clouding this issue more than helping. I hope Trevor drops by to read this whole thread.

Me neither - have had a Spamcop account for many years and have never been aware of any limit, and quickly checking my inbox I have got, for instance, an almost 20mb attachment I received last week.

You mentioned that your emails are being forwarded, and I agree that it is more likely to be a limit on the outgoing server. If the forwarding is direct from your domain host and a limit at their end turns out to be the problem if you PM me I will let you know who I use. Also (purely hypothetically now), if you are running Exchange don't forget that it has its own default attachment size limits, and so although the email made it into the inbox OK it would then be rejected when Exchange received it.

Posted

We do not limit the size of incoming e-mails, so the limit is just whatever the servers can handle.

The message limit listed in Webmail's compose screen relates *only* to sending e-mails from the Webmail interface, and does not affect the rest of the system.

E-mail is not designed for large attachments, and you really shouldn't expect an e-mail over 1 meg to get to its destination no matter where you send it from or to. Every system does have a limit, including ours, but it is hard to measure and impossible to guarantee. Additionally, your message passes through different servers and software depending on how you sent it (webmail vs SMTP server vs forwarding), each one of which could have different limits. It can hop through a bunch of different ISPs and mail hosts on its way to its destination, all of which also have their own limits and attachment policies and virus scanners that could mangle or drop your message without warning.

-Trevor

Posted

As a practical test, I just sent a 30MB file from work to my spamcop account with no issue. I have since deleted both versions. My server could not send >50MB.

Posted
...E-mail is not designed for large attachments, and you really shouldn't expect an e-mail over 1 meg to get to its destination no matter where you send it from or to. Every system does have a limit, including ours, but it is hard to measure and impossible to guarantee. Additionally, your message passes through different servers and software depending on how you sent it (webmail vs SMTP server vs forwarding), each one of which could have different limits. It can hop through a bunch of different ISPs and mail hosts on its way to its destination, all of which also have their own limits and attachment policies and virus scanners that could mangle or drop your message without warning. ...
Thanks, well worth stating, and users noting. I've often wondered ... but continue to "risk it".
Posted

Thanks for all the help guys :)

We've found the offending server with a 10MB limit along the route to Spamcop. A couple of years ago that would have seemed massive even with encoding but now it seems low, so we may have route around it, great to know we haven't run up against an upper limit at Spamcop :)

Many thanks

James

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