I need to provide a SMTP email service to a network and correctly configure the ports.
I understand SMTP uses port 25 over TCP, but have also read that SMTP is mainly used to transfer mail between mail servers and not the individual clients. Would either IMAP or POP3 be needed to send from the client to the server on port 993 or 995? or is there another port or way?
What other ports are needed to send an email via SMTP?
Thanks in advance
Related
I am developing smtp server and there is a question i don't understand about smtp handshake.
#1. mail client (outlook) -> My SMTP Server
EHLO - AUTH - FROM - TO - DATA - QUIT
It is smtp relay request. My smtp server takes the request and delivers the mail to other mail server.
#2. Other SMTP Server -> My SMTP Server
EHLO - FROM - TO - DATA - QUIT
I understood smtp flow between SMTP servers as follows. AUTH command is not necessary in this case, because AUTH command is for authentication for client to send request relay to smtp server.
#1, #2 are the flow of SMTP that i understand. What I'm curious about is how does my smtp server determine whether this request is from a client or a server. I want to decide whether to do the AUTH command through it.
If my thoughts are wrong, don't laugh too much and i ask for a kind explanation.
Thank you.
The usual modern solution is to separate SMTP submission from regular SMTP transmission traffic, and require authentication for the former, but not the latter.
The latter should only accept inbound traffic for domains you are MXing for, and run on port 25.
Regular users should be blocked from using port 25 (your ISP or corporate firewall probably already does this) and use port 587 for message submission. (Some legacy systems still use 465, but you should not.)
In actual practice, you would check at MAIL FROM whether the sender is internal, in which case reject if they are not authenticated; and otherwise, check in RCPT TO if all recipients are internal, and reject the ones which are not.
See RFC 6409 for the SMTP submission spec, and RFC 8314 for related security recommendations.
I am hosting my email server (postfix, dovecot) at home. I cannot send emails as my ISP does not allow connection via port 25. I have a linux server in the cloud with a public IP and I would like to use it as an SMTP relay (with authentication) for my email server. Is there any open source SMTP relay?
Thank you.
Regards
Zak
Hint for Debian (and most Linux distribution):
Keep sendmail (from sendmail.org) if you have significant sendmail experience.
Otherwise use Postfix.
https://wiki.debian.org/MTA
I am having a problem configuring Prestashop SMTP.
I am trying to use gmail client.
SMTP server: smtp.gmail.com
Username: xxxxxxxx#gmail.com
Password: password_of_gmail
SSL
465
Error:
Connection could not be established with host smtp.gmail.com [Cannot assign requested address #99]
Gmail has turn off 2 step vertification, POP3 enabled, and Allow less secure apps enabled too.
Maybe your server doesn't allow external SMTP access.
For example 1and1 shared hosting doesn't allow that https://github.com/PHPMailer/PHPMailer/issues/816
I want to use port 587 to send email using an SMTP server via SSL or without SSL even. Is there any free email clients that can help me out here? My port 465 and 25 are blocked
There are many email clients that may meet your demand such as Foxmail and Thunderbird.
You can add a new account with manually without automatical config.
But you should make sure that the SMTP sever is using port 587 but not port 465 or 25. This should be configured in the server.
I am trying to setup windows server 2008 smtp server to relay emails to gmail smtp. Everything appears to be setup but it is not sending emails. Could you please help me figure out whats wrong.
Below is the setup:
Windows server 2008 with SMTP server
feature installed. Need SMTP server
to forward all messages to gmail smtp
server to send.
I have google apps setup for my
domain, also I can send emails
throught my test app using
gmail smtp.
SMTP Server Configuration: By default has default smtp server virtual directory.
In Properties of that virtual smtp server changed following.
Fully qualified domain name = mydomain.com
smart host = smtp.gmail.com
TCP Port = 587
Out Bound Security = Basic Authentication(my username password for google apps email account)
In domains list under virtual smtp server. I have one default domain that's server dns. I added another one for my domain name.
With above setup i am trying to redirect all email to gmail smtp.
I tested connection to smtp.gmail.com from server on port 587 through telnet and it works.
I am trying to use above server from my web application also by just dropping emails in pickup directory. It get's picked up and also accepts request form web application but never sends an email.
I can see that it adds those emails in queue folder but it stays there forever.
When i try to send emails from web app to above server it rejects if To address is other than my domain.(Am i missing something in list of domains)
Thanks for all answers, finally found solution there is a property for maximum sessions which value was 0 by default. Changed it to 100 and it send all pending emails immediately.
Possible reasons are that some SMTP servers block the outgoing messages if there domain name mismatch, possible to prevent spam mails from being sent. So for example, I will not be able to send my email with an address abc#mydomain.com from my domain yourdomain.com.
Hope that helps.
Ensure your sending domain is the same as the google apps domain
Ensure your sending address is a real address and not just an alias
IIRC you need to use STARTTLS (SSL) not basic authentication
This souds like a DNS issue. Check your /badmail directory. It will have .bad and .bdp files in there. You can open these in notepad (there will be some binary in there).
However, it may point to the possible problem.
You may also want to try and enable logging on the SMTP service. There may be something in there.