On 2026-02-26 08:15, Fehlauer, Norbert via mailop wrote:
For this kind of testing openssl s_client command is appropriate
warning: some mailservers tolerate a bare LF in the protocol, and some do not and require CRLF (as per spec)
This bit me in the past; Microsoft's mailservers are intolerant of this and it appears edge01.systema-online.de is as well… which isn't surprising given it's Exchange.
See: [baron ~]$ openssl s_client -starttls smtp -connect edge01.systema-online.de:25 CONNECTED(00000003) … Verification: OK --- 250 XSHADOW EHLO baron.my.net 451 4.7.0 Timeout waiting for client input 40170D31C47F0000:error:0A000126:SSL routines:ssl3_read_n:unexpected eof while reading:../ssl/record/rec_layer_s3.c:322: vs (with -crlf): [baron ~]$ openssl s_client -starttls smtp -connect edge01.systema-online.de:25 -crlf CONNECTED(00000003) Verification: OK --- 250 XSHADOW EHLO baron.my.net 250-edge01.systema-online.de Hello [159.203.42.156] 250-SIZE 37748736 250-PIPELINING 250-DSN 250-ENHANCEDSTATUSCODES 250-X-EXPS NTLM 250-8BITMIME 250-BINARYMIME 250-CHUNKING 250-XEXCH50 250-SMTPUTF8 250 XSHADOW RSET RENEGOTIATING 409772A6C57F0000:error:0A000126:SSL routines:ssl3_read_n:unexpected eof while reading:../ssl/record/rec_layer_s3.c:322: M. -- Michael Brown Civilized Discourse Construction Kit, Inc. https://www.discourse.org/
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