Block incoming Telnet connections

yatinthakur

Member
Mar 27, 2014
17
0
1
cPanel Access Level
Root Administrator
Hello

I wonder how can I block incoming connections via telnet. ? so that user can not send emails using telnet server ip 25/

Or

Is there any way to enable authentication for smtp ? I am using cpanel 11.5 with exim


Thanks
Yatin
 

vanessa

Well-Known Member
PartnerNOC
Sep 26, 2006
833
28
178
Virginia Beach, VA
cPanel Access Level
DataCenter Provider
You can't really block telnet specifically - all that does is allow a connection to open to a remote server. When someone uses telnet to connect to port 25, the server doesn't see that as being any different than a mail client opening an SMTP connection.

What I suspect you're actually asking is how to prevent email from being relayed through your server. By default, cPanel configures your server to require SMTP authentication. Is there any reason you believe that your server is not set up this way?
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,913
2,202
363
Is there any way to enable authentication for smtp ? I am using cpanel 11.5 with exim
That is not a valid version of cPanel. The latest cPanel/WHM builds are version 11.42. You can verify your version of cPanel via the following command:

Code:
cat /usr/local/cpanel/version
Thank you.
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,913
2,202
363
Check to make sure that "Antirelayd" is unchecked in "WHM Home » Service Configuration » Service Manager". SMTP authentication is required as long as this service remains disabled.

Thank you.