Thanks Chirs, Please correct me if i am wrong. just sharing this if my concept is correct.
port 25 is to send email b/w mailservers. if my client(e.g. outlook) wants to send email it must use port 465 and 587 for security. port 465 is for SSL Wraped SMTP port but can also be used with TLS however some clients does not support this method. thus may fail 465 with TLS setup. Since 587 port is the new standard and client are well aware of 587+TLS. therefore the good route to go is 586 with TLS. Please correct me if i am wrong. Thanks, MYK On Sun, Apr 5, 2015 at 7:28 PM, Chris Adams <c...@cmadams.net> wrote: > Once upon a time, Muhammad Yousuf Khan <sir...@gmail.com> said: > > now the confusion part is my concept. does port 25 and 465 work together > > like FTP. port 21 and 20. like 1 port is for negotiate and another port > is > > for data? > > Port 25 is tradtiotional SMTP, aimed at server<->server communications > now (and blocked by some consumer ISPs to reduce spam). It starts in > the clear but can support STARTTLS to switch to encrypted communication. > > Port 587 is the "submission" port for SMTP. It works the same as port > 25 (including clear communications and STARTTLS support), but is > intended for client<->server communication for initial message > submission. It should require SMTP AUTH (so only authenticated mail can > be submitted). > > Port 465 was an early (non-standard) SSL-wrapped SMTP port. All > communication is encrypted (similar to port 443 for HTTP). This was > never an IANA-assigned use, and not that many things support it. Its > use is deprecated, but MS Outlook (at least some versions) only support > SSL-wrapped SMTP on port 465 (they don't handle the standard way of > connecting to 587 and then issuing STARTTLS). > > -- > Chris Adams <c...@cmadams.net> >
