Hello, When connecting to Exim 4.94, dovecot submission logs this warning: dovecot[25235]: submission(alec)<25347><QNydV8+t+oMKAgAF>: Warning: smtp-client: conn localhost:25 ([::1]:25) [1]: Received invalid EHLO response line: Unexpected character in EHLO keyword Looks like it doesn't like the underscore in "X_PIPE_CONNECT", since it's neither "isalnum" nor a dash [1]: 1598480923.401085 220 myhostname ESMTP Exim 4.94 Wed, 26 Aug 2020 18:28:43 -0400 1598480923.401906 250-myhostname Hello localhost [::1] 1598480923.401906 250-SIZE 52428800 1598480923.401906 250-8BITMIME 1598480923.401906 250-PIPELINING 1598480923.401906 250-X_PIPE_CONNECT 1598480923.401906 250-CHUNKING 1598480923.401906 250-STARTTLS 1598480923.401906 250 HELP 1598480923.409242 250 OK 1598480923.434743 250 Accepted 1598480923.578335 250- 511 byte chunk, total 511 1598480923.578335 250 OK id=1kB3uN-0006ar-HU Adding the line "pipelining_connect_advertise_hosts =" to Exim's config fixes the issue by disabling X_PIPE_CONNECT. Is this a bug in Exim or is Dovecot being too strict? Thanks, Alec [1] https://github.com/dovecot/core/blob/2.3.11.3/src/lib-smtp/smtp-syntax.c#L250
On 28/08/2020 01:11, Alec Moskvin wrote:> Hello, > > When connecting to Exim 4.94, dovecot submission logs this warning: > > dovecot[25235]: submission(alec)<25347><QNydV8+t+oMKAgAF>: Warning: smtp-client: conn localhost:25 ([::1]:25) [1]: Received invalid EHLO response line: Unexpected character in EHLO keyword > > Looks like it doesn't like the underscore in "X_PIPE_CONNECT", since > it's neither "isalnum" nor a dash [1]: > > 1598480923.401085 220 myhostname ESMTP Exim 4.94 Wed, 26 Aug 2020 18:28:43 -0400 > 1598480923.401906 250-myhostname Hello localhost [::1] > 1598480923.401906 250-SIZE 52428800 > 1598480923.401906 250-8BITMIME > 1598480923.401906 250-PIPELINING > 1598480923.401906 250-X_PIPE_CONNECT > 1598480923.401906 250-CHUNKING > 1598480923.401906 250-STARTTLS > 1598480923.401906 250 HELP > 1598480923.409242 250 OK > 1598480923.434743 250 Accepted > 1598480923.578335 250- 511 byte chunk, total 511 > 1598480923.578335 250 OK id=1kB3uN-0006ar-HU > > Adding the line "pipelining_connect_advertise_hosts =" to Exim's config > fixes the issue by disabling X_PIPE_CONNECT. > > Is this a bug in Exim or is Dovecot being too strict? > > Thanks, > Alec > > [1] https://github.com/dovecot/core/blob/2.3.11.3/src/lib-smtp/smtp-syntax.c#L250Dovecot follows the standards as strict as reasonable, with some workarounds for the bad code out there. Exim is in violation of RFC 5321, Section 4.1.1.1: ehlo-ok-rsp = ( "250" SP Domain [ SP ehlo-greet ] CRLF ) / ( "250-" Domain [ SP ehlo-greet ] CRLF *( "250-" ehlo-line CRLF ) "250" SP ehlo-line CRLF ) ehlo-greet = 1*(%d0-9 / %d11-12 / %d14-127) ; string of any characters other than CR or LF ehlo-line = ehlo-keyword *( SP ehlo-param ) ehlo-keyword = (ALPHA / DIGIT) *(ALPHA / DIGIT / "-") ; additional syntax of ehlo-params depends on ; ehlo-keyword ehlo-param = 1*(%d33-126) ; any CHAR excluding <SP> and all ; control characters (US-ASCII 0-31 and 127 ; inclusive) The underscore is not supported by the standard (only dash). Is Exim doing this by default? In that case we may need to add a workaround for it. Regards, Stephan.
On 03.09.20 01:57, Stephan Bosch wrote:>> ?? 1598480923.401085 220 myhostname ESMTP Exim 4.94 Wed, 26 Aug 2020 >> 18:28:43 -0400 >> ?? 1598480923.401906 250-myhostname Hello localhost [::1] >> ?? 1598480923.401906 250-SIZE 52428800 >> ?? 1598480923.401906 250-8BITMIME >> ?? 1598480923.401906 250-PIPELINING >> ?? 1598480923.401906 250-X_PIPE_CONNECT >> ?? 1598480923.401906 250-CHUNKING >> ?? 1598480923.401906 250-STARTTLS >> ?? 1598480923.401906 250 HELP >> ?? 1598480923.409242 250 OK >> ?? 1598480923.434743 250 Accepted >> ?? 1598480923.578335 250- 511 byte chunk, total 511 >> ?? 1598480923.578335 250 OK id=1kB3uN-0006ar-HU >>> The underscore is not supported by the standard (only dash). > > Is Exim doing this by default? In that case we may need to add a > workaround for it.This was added to the default feature set of Exim with 4.93 as implementation of https://www.ietf.org/archive/id/draft-harris-early-pipe-01.txt Gr??e, Sven. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 833 bytes Desc: OpenPGP digital signature URL: <https://dovecot.org/pipermail/dovecot/attachments/20200903/0562744b/attachment.sig>