SMTP for Cloud VPS Mail Server – A Real World Scenario - Comic

Looking to set up a VPS mail server? Atlantic.Net can help. We do our best to learn from our customers and provide content in our blog relevant to their needs. While we have broad information available through our site, clients often turn to our support staff for detailed queries.

By gathering questions from our hosting consultants, we can better tailor the information we provide to meet user needs. We call this series of everyday interactions between our clients and our consultants Real-World Scenarios.

In the below transcript, the client is interested in SMTP for a cloud VPS environment. We will first review the questions and answers, then discuss email methods and another concern addressed – swap files.

SMTP for a mail server

Client: I’m looking at the possibility of setting up a new Cloud VPS with about 3 VPS instances: for mail, the web, and database. I have a few questions. I’m primarily looking at Cloud VPS options. First, is your cloud traffic metered or not?

Consultant: Only outbound traffic is metered. Please take note that we do provide each cloud server with 1TB of free outbound transfer per month.

Client: OK… Would the traffic between two VPS’s in the same data center be metered or slowed due to edge routing or similar?

Consultant: Traffic between two VPS’s is not affected by edge routing.

Client: Okay, good. Do your VPS’s provide any swap, or does that have to be set up manually as a swap file on the disk after the fact?

Consultant: You would have to set up a swap file on the disk.

Client: Assuming common VPS standards, do you control the kernel?

Consultant: Atlantic.Net does not control the kernel.

Client: Will the kernel support TUN/TAP, or is that disabled?

Consultant: The kernel should support TUN/TAP: we do not disable it.

Client: I notice that SMTP is blocked according to your Cloud VPS FAQ. As mentioned earlier, I intend to run a mail server. Would I be able to get this block lifted for that purpose?

Consultant: In order to unblock SMTP traffic, you will need to provide our technical department with a brief description of your intended use. There should be no issues as long as you adhere to Atlantic.Net’s AUP agreement.

What is SMTP?

SMTP stands for Simple Mail Transfer Protocol. It is a form of TCP/IP protocol used to enable incoming and outgoing email messages. TCP/IP, or Transmission Control Protocol/Internet Protocol, is the standard means of web interaction. Every computer or device capable of accessing the Internet sends and receives data through a TCP/IP application.

SMTP is not well suited to handle incoming messages, so it is typically combined with one of two other common email protocols – POP3 (Post Office Protocol 3) or IMAP (Internet Message Access Protocol).

With POP3, all email remains on the server until the relevant user checks it; at that point, it is downloaded and deleted from the server. Typically POP3 is used for personal rather than business email. With IMAP, the use of which is more widespread in business settings, you can manage mail on your server without having to download it. It’s practical to use IMAP in conjunction with SMTP, with the former configured to receive messages and the latter configured to send them.

The most popular SMTP application for Linux and FreeBSD is send email. You can either use the open-source version or a proprietary offering – Sendmail – that is bundled with a POP3 program. If you’re using a Windows environment, Microsoft Exchange comes with SMTP functionality preinstalled.

What is a swap file?

A swap file enables a VPS or other server to designate a portion of the hard drive to serve as additional memory as needed. If the operating system needs RAM (random access memory) to run a certain application, it can transfer underutilized resources from an application onto the hard drive. In this manner, memory can be swapped back and forth, giving your environment greater flexibility.

The creation of swap files is referred to as virtual memory. The practice makes it possible to run additional programs that would otherwise be possible without as many latency issues (although cloud systems generally optimize availability).

Swap files can be either permanent or temporary. The former is generally the case with Windows systems: swapping occurs on a case-by-case basis, with files generated for one-time use. The latter is typically the case with Linux and FreeBSD: those systems set aside a section of the hard drive for swapping. Permanent files tend to result in higher performance, while temporary ones are better for keeping resources free on an ongoing basis.

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Finding cloud VPS options for mail servers

Atlantic.Net has been in business for 20 years. Throughout that time, we have remained on the cutting edge of IT equipment and practices. We now offer a full line of cloud VPS hosting packages, everyone utilizing solid-state drive (SSD) cloud hosting servers for up to 100 times the performance vs. standard HDD drives. We also offer dedicated hosting and VPS hosting services. Live support is available 24/7.

By Kent Roberts