On 16 Apr 2019, at 04:27, Konstantin Boyandin (lists) via Exim-users <[email protected]> wrote: > Is there any Exim setting capable of re-formatting long headers (i.e., split > them into several lines, each below 998 character limit) etc such headers, > but allowing the incoming mail nonetheless?
I feel your pain; I had to migrate 20000 or so student mailboxes from Gmail to Exchange Online (Office 365) a couple of years back and there were thousands of messages with over-long lines (but not headers!) and EOL would not accept them. We used imapsync which allows in-flight modification of the message, so we split at 998 chars and added \r\n as a line break. Anyhow... I don’t think there is a generic ‘fold over-long header lines’ option, as that interferes with the mantra of not changing the message in flight. Main config option ‘header_line_maxsize’ is both your friend and enemy here - the default is 0; you clearly have it set to 998. If you want to fold a header, you’ll need to remove and replace the header: * Set global option ‘header_line_maxsize' to 0 (or don’t specify it at all) * Set an ACL variable (in the DATA ACL) to contain the value of the header if it’s longer than 998 chars * Use sg on that variable to add ‘\r\n ‘ every 990 characters * Use headers_remove and headers_add on the appropriate transport to replace the over-long line header HOWEVER: I don’t think this is advisable, as you could break DKIM signing if the over-long header is included in the signature. You may also need to experiment on whether this is best applied using header_thing or rheader_thing - probably the latter. Graeme -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
