Does Postfix Have a Hard-Coded Upper Limit to Message Size?

Virtualmin
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SYSTEM INFORMATION
OS type and version Rocky 8.x
Webmin version 2.001
Virtualmin version 7.3 Pro
Related packages Postfix

I’m not asking how to change the limit. I already know how to do that. What I’m wondering is whether there’s a hard max. It seems to vomit on anything over 26500000.

Thanks,

Richard

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What is the exact error? Is it a problem when sending or receiving or both?

I am unaware of a hard limit in Postfix…are you sure it’s Postfix and not some other layer of the stack? (e.g. procmail)

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Error while checking current Postfix configuration. Please manually fix Postfix configuration.

postfix: fatal: bad numerical configuration: message_size_limit = 30,720,000

No, I’m not sure it’s not some other layer. The error message references Postfix, so I assumed it was there; but I was unable to find any limitation in the Postfix docs.

I will check. Thanks.

Richard

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postconf message_size_limit
postconf -d message_size_limit

?

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[root@server2 postfix]# postconf -d message_size_limit
message_size_limit = 10240000
[root@server2 postfix]# postconf message_size_limit
message_size_limit = 34000000

Somewhat bizarrely, it’s working now.

Richard

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Now it’s working fine at message_size_limit = 128000000.

I farted around with this for an hour the other day and it errored out every time. Now it works fine. I have no idea why.

Thanks,

Richard

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That’s not valid syntax. No commas allowed.

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Aha.

I can’t imagine that I inserted commas in the UI when there were none there in the default value. It’s possible, though. Sometimes I’m doing too many things at once.

This time I directly edited main.cf. I tend to be more cautious in the shell.

Thanks,

Richard

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We could probably protect you from making that mistake in the GUI. It’s just not really come up often, thought I’m pretty sure I saw another post with the same error a day or two ago (but I can’t remember ever seeing it before so maybe it was another post of yours and the same error was just in there ancillary to what you were asking about).

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Probably my post. 26500000 was enough for the client in question then, anyway. He really only needed 20MB.

Another client I’m planning to migrate from cPanel to Virtualmin currently has a 250MB limit (which I think is kind of absurd) but can get away with half that. He has to send blueprints, pictures, videos, etc., but they’re never more than 100MB total. Now that I know Postfix can do that, it’s another hurdle behind me.

Yeah, stripping out the commas would be a good idea. I have no idea how you’d do that in Perl, but it seems worthwhile. I can’t be the first idiot who made that mistake and doesn’t remember making it.

Thanks again,

Richard

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If we do add protection against this, it wouldn’t modify it silently, it would just give you an error when trying to save bogus options (which we do in some modules for some options that are commonly confused).

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