Email sender is using an old mail client

jason_isl

Registered
Dec 27, 2017
2
0
1
HongKong
cPanel Access Level
Root Administrator
Dear All,

My email cannot receive any email from a domain. And i have check the Delivery Report, there are no any record about it. But i have find some error in exim_maillog.

2018-01-07 02:32:40 TLS error on connection from exchtp.xxxx [xxxxx]:5945 (SSL_accept): error:1408A0C1:SSL routines:ssl3_get_client_hello:no shared cipher
2018-01-07 02:32:40 SMTP connection from exchtp.xxxx [xxxxx]:5945 closed by EOF

I find out some information. Those said sender is using an old mail client. Can I fix the problem on my side?

Thanks a lot
Jason
 

cPWilliamL

cP Technical Analyst II
Staff member
May 15, 2017
258
30
103
America
cPanel Access Level
Root Administrator
Hi @jason_isl,

Sorry to hear you're facing issues with an outdated mail client. I'd recommend updating the client or OS to ensure that it's using modern and secure ciphers/protocols; however, I understand that can be difficult. In cPanel 68, on new servers, we updated the cipher list:
68 Release Notes - Version 68 Documentation - cPanel Documentation

You may try setting the old ciphers below at WHM > Service Configuration > Mailserver Configuration: SSL Cipher List:
Code:
ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:!DSS
However, realize that this decreases your security for all users.

Thanks,