I need a solution
Hello.
My customer receives a 421 status in return to RCPT TO command when trying to send a mail to a messagelabs customer. Please see a log example below.
Sending mail from mx00.mpac.com, 185.37.248.215, Exchange 2010
IP Investigation at http://ipremoval.sms.symantec.com/lookup/ did return that it's not blocked.
Thank you and kind regards,
Hannes
2018-11-02T10:31:33.385Z,Internet,08D640ADAEC9E854,2,192.168.2.14:52004,52.29.12.9:25,<,"220 mail555.messagelabs.com ESMTP Fri, 02 Nov 2018 10:31:33 +0000",
2018-11-02T10:31:33.385Z,Internet,08D640ADAEC9E854,3,192.168.2.14:52004,52.29.12.9:25,>,EHLO mx00.mpac.com,
2018-11-02T10:31:33.401Z,Internet,08D640ADAEC9E854,4,192.168.2.14:52004,52.29.12.9:25,<,250-mail555.messagelabs.com Hello ip-100-113-13-169.eu-central-1.aws.symcld.net [100.113.13.169],
2018-11-02T10:31:33.401Z,Internet,08D640ADAEC9E854,5,192.168.2.14:52004,52.29.12.9:25,<,250-SIZE 52428800,
2018-11-02T10:31:33.401Z,Internet,08D640ADAEC9E854,6,192.168.2.14:52004,52.29.12.9:25,<,250-8BITMIME,
2018-11-02T10:31:33.401Z,Internet,08D640ADAEC9E854,7,192.168.2.14:52004,52.29.12.9:25,<,250-PIPELINING,
2018-11-02T10:31:33.401Z,Internet,08D640ADAEC9E854,8,192.168.2.14:52004,52.29.12.9:25,<,250-CHUNKING,
2018-11-02T10:31:33.401Z,Internet,08D640ADAEC9E854,9,192.168.2.14:52004,52.29.12.9:25,<,250-STARTTLS,
2018-11-02T10:31:33.401Z,Internet,08D640ADAEC9E854,10,192.168.2.14:52004,52.29.12.9:25,<,250-PRDR,
2018-11-02T10:31:33.401Z,Internet,08D640ADAEC9E854,11,192.168.2.14:52004,52.29.12.9:25,<,250 HELP,
2018-11-02T10:31:33.401Z,Internet,08D640ADAEC9E854,12,192.168.2.14:52004,52.29.12.9:25,>,STARTTLS,
2018-11-02T10:31:33.432Z,Internet,08D640ADAEC9E854,13,192.168.2.14:52004,52.29.12.9:25,<,220 TLS go ahead,
2018-11-02T10:31:33.432Z,Internet,08D640ADAEC9E854,14,192.168.2.14:52004,52.29.12.9:25,*,,Sending certificate
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,20,192.168.2.14:52004,52.29.12.9:25,*,,Remote certificate
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,21,192.168.2.14:52004,52.29.12.9:25,*,"CN=mail555.messagelabs.com, O=Exim Developers, C=UK",Certificate subject
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,22,192.168.2.14:52004,52.29.12.9:25,*,"CN=mail555.messagelabs.com, O=Exim Developers, C=UK",Certificate issuer name
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,23,192.168.2.14:52004,52.29.12.9:25,*,00,Certificate serial number
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,24,192.168.2.14:52004,52.29.12.9:25,*,9387CEF45FD5C3EA68ADA0DDEAF6B6B7F831DA2D,Certificate thumbprint
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,25,192.168.2.14:52004,52.29.12.9:25,*,mail555.messagelabs.com,Certificate alternate names
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,26,192.168.2.14:52004,52.29.12.9:25,*,,"TLS protocol SP_PROT_TLS1_0_CLIENT negotiation succeeded using bulk encryption algorithm CALG_AES_256 with strength 256 bits, MAC hash algorithm CALG_SHA1 with strength 160 bits and key exchange algorithm CALG_ECDHE with strength 256 bits"
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,27,192.168.2.14:52004,52.29.12.9:25,*,,Received certificate
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,28,192.168.2.14:52004,52.29.12.9:25,*,9387CEF45FD5C3EA68ADA0DDEAF6B6B7F831DA2D,Certificate thumbprint
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,29,192.168.2.14:52004,52.29.12.9:25,>,EHLO mx00.mpac.com,
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,30,192.168.2.14:52004,52.29.12.9:25,<,250-mail555.messagelabs.com Hello ip-100-113-13-169.eu-central-1.aws.symcld.net [100.113.13.169],
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,31,192.168.2.14:52004,52.29.12.9:25,<,250-SIZE 52428800,
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,32,192.168.2.14:52004,52.29.12.9:25,<,250-8BITMIME,
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,33,192.168.2.14:52004,52.29.12.9:25,<,250-PIPELINING,
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,34,192.168.2.14:52004,52.29.12.9:25,<,250-CHUNKING,
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,35,192.168.2.14:52004,52.29.12.9:25,<,250-PRDR,
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,36,192.168.2.14:52004,52.29.12.9:25,<,250 HELP,
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,37,192.168.2.14:52004,52.29.12.9:25,*,71,sending message
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,38,192.168.2.14:52004,52.29.12.9:25,>,MAIL FROM:<xxxxxx@mpac.com> SIZE=240433,
2018-11-02T10:31:33.479Z,Internet,08D640ADAEC9E854,39,192.168.2.14:52004,52.29.12.9:25,>,RCPT TO:<xxxxxxxx@xxxxxxxxx.de>,
2018-11-02T10:31:33.494Z,Internet,08D640ADAEC9E854,40,192.168.2.14:52004,52.29.12.9:25,<,250 OK,
2018-11-02T10:31:33.494Z,Internet,08D640ADAEC9E854,41,192.168.2.14:52004,52.29.12.9:25,<,421 Service Temporarily Unavailable,
2018-11-02T10:31:33.494Z,Internet,08D640ADAEC9E854,42,192.168.2.14:52004,52.29.12.9:25,>,QUIT,
2018-11-02T10:31:33.494Z,Internet,08D640ADAEC9E854,43,192.168.2.14:52004,52.29.12.9:25,-,,Local
0