On 11/10/11 19:17, Carlos Mennens wrote:
I asked a user today to make sure his incoming and outgoing email was using TLS. He told me it wasn't possible because my Dovecot / Postfix daemons were only listening on TCP 25 & 143 according to a port scan he did. He told me the only way I could enable encrypted secure sessions between the client & server is to enable port 993 (IMAPs).
Yes you are right. Port 993 is for IMAPS (SSH). TLS is normally on the same port as plain.
The difference between SSH and TLS is that with SSH the encryption is set up before any application communication takes place. i.e all application packets are contained in the encrypted payload. With TLS the application starts communication and then the application sets up encryption of its payload.
Dick