Usermail tips and requests Blog

Many customers have reported problems sending mail using secure.usermail.com as their SMTP server.  Upon investigation, we usually find that the ISP has blocked external access to port 25. In the last article, I explained why email must connect to port 25 in order to be accepted by the MTA (Mail Transfer Agent) and relayed for local delivery or routed to another email server.  I am going to explain why some customers must use port 2525 instead.

A popular method of sending UCE or Unsolicited Commercial Email is to infect PCs residing on DSL or Cable broadband connections.  Through malicious, and illegal means, a spammer is able to install hidden software on a PC if it is not protected by a firewall and anti-virus software.  This hidden software allows for this spammer to have remote access to the PC.  Once the perpetrator has infected a large number of machines, a mass emailing is sent out selling the likes of low rate Mortgages and Viagra.  The amount of mail that can be sent out in a matter of an hour with 1,000 infected machines is in the millions!  Please read this article for more information:http://www.ftc.gov/bcp/conline/pubs/alerts/whospamalrt.htm

Because of this method to send spam, many ISPs have chosen to block access to port 25 to any other servers than their own email servers.  Because of this, many of Usermail.com’s customers either have to use their ISP’s outgoing email server, or use port 2525 for their outgoing mail on secure.usermail.com.

In case your wondering:

Q: How does the server accept mail on port 2525 when you said port 25 is the standard?

A: Our servers use port 25 but also listen on port 2525 to accommodate those who have port 25 blocked but still want to use Usermail.com for their outgoing email.

Q: What is the difference between using my ISP’s SMTP (outgoing) server or Usermail.com’s?

A: The difference is minimal.  In fact, because you are connected through your ISP’s network, sending mail through your ISP will always be faster.  You want to make sure you use your Usermail.com address in your email client’s “From” field however.

In the next article, I will explain how to change the default port of 25 to 2525 in the more popular clients such as Outlook, Entourage, Outlook Express, etc.

The Internet uses a mechanism of transporting data called TCP/IP.  Built into the framework of TCP/IP are many types of traffic.  Some examples are web pages (http and https), FTP, Email retrieval (POP3 is one), and Sending email (SMTP).

SMTP stands for Simple Mail Transfer Protocol. To put it in simple terms, it is the framework designed to run over TCP/IP for the purpose of relaying mail.  What is relaying mail?  When Usermail.com takes your messages and transfers it to a Gmail.com server, this is considered a relay.

Now, let’s take this a step further.  Based on the requirements of TCP/IP, each service needs to use specific ports.  There are more than 65,000 ports that TCP/IP uses, but port 25 has been exclusively reserved for SMTP traffic.  So, when you send an emailing from Usermail.com to Gmail, our servers will connect to the servers at Gmail.com on port 25 and relay the message.

Hopefully, this explains why, when setting up your email client, the outgoing server uses port 25 as its default port.

In my next article, I will explain why many customers have to use port 2525 in order to relay through Usermail.com.

Brian F.

Hello all,

We have placed this up so that our customers can easily tell us what we are doing right, and what we are doing wrong.  We would also like to have input as to what you would like to see done differently or a feature request.  Because our support team will be monitoring new posts, feel free to post general support requests as well.

We hope you choose to use this tool in order to communicate your ideas.

Thank you,

Brian F.