Search results
Results from the WOW.Com Content Network
Late 1998 this was revoked when STARTTLS was standardized. [2] With STARTTLS, the same port can be used with or without TLS. The use of well-known ports for mail exchanges communicating with SMTP was discussed in particular at the time. [3] Port 465 currently shows [4] as registered for both Source-Specific Multicast [5] and submissions.
Several protocols use a command named "STARTTLS" for this purpose. It is a form of opportunistic encryption and is primarily intended as a countermeasure to passive monitoring . The STARTTLS command for IMAP and POP3 is defined in RFC 2595 , for SMTP in RFC 3207 , for XMPP in RFC 6120 and for NNTP in RFC 4642 .
Email is submitted by a mail client (mail user agent, MUA) to a mail server (mail submission agent, MSA) using SMTP on TCP port 587. Most mailbox providers still allow submission on traditional port 25. The MSA delivers the mail to its mail transfer agent (MTA). Often, these two agents are instances of the same software launched with different ...
Settings may be in a different location in each email client, though the AOL server and port settings will always be the same. For additional questions specific to the email client, check the manufacturer’s website. Manufacturers cannot answer questions about your AOL Mail settings, or your AOL username or password.
Only servers listening on port 587, or private servers, should be configured that way, not a Message eXchange (MX). However, the historical trait that SMTP is not authenticated by default results in a different behavior with regard to access protocols, in some cases; for example, when using AUTH EXTERNAL after STARTTLS. [9]
While recent email clients use port 587 by default, older ones still propose port 25. Users have to change the port number manually in the latter case. It is also possible that the MUA may automatically discover which server provides the MSA for a given domain, looking up the SRV records for that domain.
The STARTTLS extension allows the use of Transport Layer Security (TLS) or Secure Sockets Layer (SSL) to be negotiated using the STLS command, on the standard POP3 port, rather than an alternate. Some clients and servers instead use the alternate-port method, which uses TCP port 995 (POP3S).
Network address translation can be used to intercept all port 25 (SMTP) traffic and direct it to a mail server that enforces rate limiting and egress spam filtering. This is commonly done in hotels, [23] but it can cause email privacy problems, as well making it impossible to use STARTTLS and SMTP-AUTH if the port 587 submission port isn't used.