North American Network Operators Group
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Re: ingress SMTP

  • From: Daniel Senie
  • Date: Wed Sep 03 17:57:52 2008
At 12:48 PM 9/3/2008, you wrote:

Do you operate your mailserver on a residential cablemodem or adsl
rather than a business account?

No, we co-lo equipment at a professional facility that our customers on any type of connection need to have access to send mail through, regardless of whether their ISP blocks the standard ports or not.


-Justin Scott, GravityFree


I've been running a similar operation for over a decade, offering email services, web services and collocation to businesses from the tiny to the multinational. We have, since the beginning, provided instructions on using port 587 and port 465 for email submission. This is not hard to explain, and it has never been a problem for our customers or their tech folks to accomplish.

Our servers are in data centers, our customers are on DSL, cable or even dialup circuits. We assume port 25 will be blocked, and while it isn't always, starting with that assumption simplifies matters. We also encourage our customers to always use TLS or SSL for all exchanges with the mail servers.

Because we have many users who are road warriors, they never know who their local access ISP will be. Getting them set up for 587 or 465 before they leave home has always kept folks out of trouble. And those few who don't heed our advice have had their email hijacked by hotel networks that consume traffic to any remote port 25 themselves in an attempt to "help." So again, just get your customers configured right at the start, and there will be few support calls on the subject.

This is just part of being a third-party supplier of email services in the current reality.

Dan