ssl - Postfix pop3-ssl connection

Question

I install mail server with postfix under ubuntu 16.04 lts. After config pop3-ssl, i have this error when i telnet the server via 995.

pop3d-ssl: couriertls: accept: error:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol 

this is the config of pop-ssl

SSLPORT=995
SSLADDRESS=0
SSLPIDFILE=/var/run/courier/pop3d-ssl.pid
SSLLOGGEROPTS="-name=pop3d-ssl"
POP3DSSLSTART=YES
POP3_STARTTLS=YES
POP3_TLS_REQUIRED=0
COURIERTLS=/usr/bin/couriertls
TLS_STARTTLS_PROTOCOL=TLS1
TLS_KX_LIST=ALL
TLS_COMPRESSION=ALL
TLS_CERTS=X509
TLS_CERTFILE=/etc/ssl/private/vpsabc.example.net.pem
TLS_TRUSTCERTS=/etc/ssl/certs
TLS_VERIFYPEER=NONE
TLS_CACHEFILE=/var/lib/courier/couriersslcache
TLS_CACHESIZE=524288
MAILDIRPATH=Maildir

Answer 1

您的服务器配置没有问题 - telnet 不支持 SSL，因此它不会进行 SSL 握手等。您需要使用 sslclient 来测试通过 SSL/TLS 运行的东西。 https://blog.yimingliu.com/2009/01/23/testing-a-pop3-server-via-telnet-or-openssl/