Before I go into the list of VPS providers with port 25 open, I will like to talk about port in general. This will help us to have a better understanding of what ports are and the reason why we should open anyone, say port 25.
What is port
According to TechTarget, a port is a way to identify a specific process to which an internet or other network message is to be forwarded when it arrives at a server. It is an internet protocol that allows a user to communicate between servers.
Simply put, ports allow connections to happen. To perform some actions on your computer you need certain ports to be open. For instance:
- To connect to a Linux machine you need port 22 to be open. Look at the picture below. This is a putty SSH to establish a connection to a Linux machine.
- Connecting to anther window machine Via RDP is established via port 3389
- SQL database systems like MySQL are established via port 3306.
- Connecting to websites as you are doing right now on this site uses port 80
To send emails from your server to your client’s servers you need port 25 to be open in your server.
Why do we need port 25 to be open?
Port 25 is an internet protocol that must be open on your computer or server to allow you to send and receive emails. In the same way, you need port 22 to be open to help establish a remote connection to a Linux machine, you need port 25 to be opened on your machine or server to help you receive and send messages.
How to check if port 25 is open
One of the best tools in the market today to check whether or not port 25 is open is yougetsignal. Just input your machine IP address in the IP address field. Put the port number you want to check in the port number field. You will notice that if you click on check, you will see whether or not the port you are looking for is open.
The picture below shows an IP address check by yougetsignal with port 25 closed ……..
This shows that port 25 is closed for this machine. Meaning I can’t send emails from this server but I can receive.
Note: If you check the status of my port 25 from the picture above it shows that my port is closed. But, notice that I can still receive emails from my server. So, when we talk about port 25 being open, it means it is open for outgoing mails. This means you can send and receive emails, but when your server port is closed you will be able to receive emails but you cant send. Summarily port 25 is open by default for incoming mails but isn’t for outgoing mails. Hope you get the point now? I hope you do 
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Why port 25 is blocked by VPS providers
In today’s world, spamming is a thing of great concern to email clients like Gmail, yahoo, outlook, etc. According to Forbes, 320 billion spam emails are sent every day, and 94% of malware is delivered via this medium. This is the major reason why most internet service providers ( ISPs ) are blocking their port 25. Even a few of them that open their port 25 for outgoing mails are very strict about spam, and won’t hesitate to block any machine or IP address that is triggering spam in their system. You might be wondering how ISPs detect spam? Well, let’s see
How do ISPs detect Spam?
There are spam detection databases such as spamhaus.org that blacklists IPs that indicate potential spamming.
As a result of this, email clients have leveraged on third-party IP blacklist databases to assign a reputation to your server or sending IP. IP reputation reflects the quality of emails sent out of a server. This implies that Email clients are scoring your server based on how genuine emails you are sending out of your server. This helps them to decide whether to place your emails in their customer’s inbox or the hell of the spam folder. Once ISPs records lower reputations, emails from their server will be going to the spam folder. This will make them record low sales. Low Sending scores which is a function of reputation will also make them have low credibility as a company.
Also, there are certain laws by the government that places fine on any ISP that allow their servers to be used for spamming. To save themselves from these unwanted fines, ISPs simply block their port 25.
Effects of port 25 Block
But, all this outright ban on port 25 by ISP’s arent favoring Email marketers. We all know that the ROI in email marketing is up to 4400%. Subscribing to email marketing companies for instance: systeme.io, getresponse, etc is quite expensive. To maximize our ROI in email marketing, we still need to find a workaround for the port 25 issues. This will help us to set up our mailing system and send unlimited emails for as low as $12. You can check my Postal SMTP Setup Guide to learn how to build your own SMTP server for free.
I have made a list of VPS providers with port 25 open.
Also note that these VPS providers change their policies from time to time hence, if you notice that any of these VPS providers no longer sell VPS with port 25 open, I request you email me at [email protected] so that we can fix things together and I can also keep this article up to date.
List of VPS providers with port 25 open
Here is the list of VPS providers with port 25 open for outgoing mail.
The above VPS providers are the one that opens port 25 by default. There are a lot of other VPS companies that allows mailing but you just have to first configure an A record and reverse DNS after purchase, then you can message them to open the port 25 for you. The essence of the A record and reverse DNS configuration is to properly map your domain. The Rdns specifically helps them to know the origin of an email traffic. This will help ISPs perform a reverse lookup or query to know the IP address where suspected spam emails are originating from.
The Rdns concept is also used in web hosting to track the origin of traffic coming to a website, and from the data available the location of such traffic can be determined. Though this is not a criteria for reaching mail servers. The below VPS providers will open port 25 once you correctly configure the address record and reverse DNS. One good thing is that some of them gives you free $100 credit to try their platforms out totally for free. So feel free to try them below as there is no cost on you.
There are turns of VPS providers with port 25 open. The ones listed above are the ones I have used and tested. You are free to use any VPS provider you are comfortable with, but make sure to do your due research and contact their support team to ensure port 25 is open on their server before you proceed with payment.
So, let me know what your thoughts are in the comment section. Let me know the current VPS providers you use currently whose IPs aren’t on the blacklist so that we can check them out and improve on the tutorial and help more people. Also let me know if you finds out that any of the above listed VPS services I listed above aren’t allowing port 25 open any longer. Don’t forget to post any issue you have on the forum and I will be there to help you ASAP.