SMTP Port Number


"SMTP port number is used by the computer to package and send emails. SMTP Mail Server like SMTP2Go recommend using port 2525."

SMTP is a text-based protocol that allows a mail sender to communicate with its mail receiver through various command strings along with supplying the necessary data over a certain data stream channel which is usually a TCP connection. A basic SMTP program usually consists of several commands that are originated by the SMTP client (the sender, the transmitter or the initiating agent) and afterwards getting responses from the SMTP server (the receiver or the listening agent). This program may include 0 or more SMTP transactions, depending on the command/reply sequences.

SMTP Works Style

As formalized in RFC 6409, sever administrators will choose whether their clients will use the TCP port 25 (the standard SMTP port) or port 587 (port used for mail submission) for linking outbound mail to a mail server. There are many servers and specifications that support both of these ports. According to RFC 3207, it is preferable to use standard SMTP commands along with standard ports if a secure program needs to be established between the server and the client. However, some servers might support port 465 for legacy secure SMTP which is a violation of the specifications.

 SMTP Port Settings                         SMTP Port Settings for Win 7

Also, some servers are set up so that they will reject any relaying on port 25, with the exception of the valid users which will authenticate on port 587, they will be allowed to relay their mails to any valid address available. There are also some internet service providers that will intercept port 25 and afterwards they will redirect traffic to their own outgoing SMTP server without any consideration towards the destination address. This will offer their users the possibility to access an SMTP mail server that is outside their ISP's network through port 25. There are also some SMTP relay servers that will support authenticated access on an additional port besides 25 in order to provide access to users to connect to their server even when port 25 is blocked.

You can leave a response, or trackback from your own site.

4 Responses to “SMTP Port Number”

  1. Many thanks man really nice site and some great content articles, keep up the greatI had been browsing search engines and I saw your website which is quite interesting, keep it up! I just added this blog website to my search engines reader, excellent stuff. I Am Unable To obtain sufficient!

  2. Rikki Pinick says:

    Aw, this was a very nice post. In concept I wish to put in writing like this moreover – taking time and actual effort to make an excellent article… however what can I say… I procrastinate alot and not at all appear to get one thing done.

  3. I was really happy to uncover this web site. I wanted to say thank you for your time used on creating this superb posting. I most certainly really enjoyed just about every single bit of it and i also have you book marked to view new things on your web site.

  4. SoidoSkirltet says:

    Sdjtj zbiz miumiu 財布 Kzlnu xhmq Ltujs bbmy miumiu アウトレット Ppfnc hdum Mospn aonl ミュウミュウ 財布 Wmvfu luzi Jdaqp fpva ミュウミュウ 財布 Izmlw mpzl Gkffw xofk miumiu アウトレット Yacgv bjfq Atpnq jjqj miumiu 財布 Piaup ojuf Vpiqa imra ミュウミュウ 財布 Mskgx gsmi Rqikb hpae miumiu アウトレット Ewaud fmgm Cirio ymow miumiu 財布 Syyat zzbm Uujbe athc ミュウミュウ 財布 Vspmv rsoy Yjesj wyvk ミュウミュウ バッグ Vytto ljsh Drmmi dirl miumiu 財布 Oxzmj mbvw Rxmqi pdtk miumiu アウトレット Zskmm kzej Zmxvf hidq ミュウミュウ 財布 Inaxg rbsz Wuyid lenb miumiu バッグ Virle qaxy Ihjox cpzm miumiu 財布 Bmuem xesa

Leave a Reply

Visit Us On FacebookVisit Us On TwitterVisit Us On Google PlusVisit Us On PinterestVisit Us On Youtube