ZitatOriginal geschrieben von harlekyn
587 ist ja auch fuer Mail Submission - verschluesseltes SMTP.
Diese Port-Nummer stammt nicht von mir, wie du hier ja sehr einfach nachlesen kannst.
ZitatGenau das tun sie - nur erwartest du was anderes
Wenn google genau das tut, dann erwarte ich auch, daß der Server auf Port 143 antwortet.
ZitatPort 143 ist IMAP, 993 ist IMAPS.
Ach nein, wirklich?
Port 993 ist seit RFC 2595 vom Juni 1999 überholt. Ich zitiere mal daraus:
"7. imaps and pop3s ports
Separate "imaps" and "pop3s" ports were registered for use with SSL.
Use of these ports is discouraged in favor of the STARTTLS or STLS
commands.
A number of problems have been observed with separate ports for
"secure" variants of protocols. This is an attempt to enumerate some
of those problems.
- Separate ports lead to a separate URL scheme which intrudes into
the user interface in inappropriate ways. For example, many web
pages use language like "click here if your browser supports SSL."
This is a decision the browser is often more capable of making than
the user.
- Separate ports imply a model of either "secure" or "not secure."
This can be misleading in a number of ways. First, the "secure"
port may not in fact be acceptably secure as an export-crippled
cipher suite might be in use. This can mislead users into a false
sense of security. Second, the normal port might in fact be
secured by using a SASL mechanism which includes a security layer.
Thus the separate port distinction makes the complex topic of
security policy even more confusing. One common result of this
confusion is that firewall administrators are often misled into
permitting the "secure" port and blocking the standard port. This
could be a poor choice given the common use of SSL with a 40-bit
key encryption layer and plain-text password authentication is less
secure than strong SASL mechanisms such as GSSAPI with Kerberos 5.
- Use of separate ports for SSL has caused clients to implement only
two security policies: use SSL or don't use SSL. The desirable
security policy "use TLS when available" would be cumbersome with
the separate port model, but is simple with STARTTLS.
- Port numbers are a limited resource. While they are not yet in
short supply, it is unwise to set a precedent that could double (or
worse) the speed of their consumption."
Aktuell ist übrigens RFC 3501 von März 2003.
