Retrieve remote FTP or SMTP TLS server certificate

February 26, 2013

With SSL protected resources it is easy to find a command line to retrieve the certificate. Following is documented at many places:

openssl s_client -connect www.google.com:443

But if you use use this with a TLS server, be it SMTP or FTP you’ll get

CONNECTED(00000003)
527654:error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol:s23_clnt.c:607:

The solution ins quite easy (if you know it) .. use following command line:

openssl s_client -connect ftp.xxxx.at:21 -starttls ftp

or

openssl s_client -connect smtp.xxxx.at:25 -starttls smtp

No Comments yet »

RSS feed for comments on this post. TrackBack URI

Leave a comment

XHTML: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

Powered by WordPress
Entries and comments feeds. Valid XHTML and CSS. 67 queries. 0.229 seconds.