Archive for the 'domain registration' Category

Problems with spam filters…

Wednesday, January 10th, 2007

This last few months I have noticed an increasing problem with legitimate emails getting blocked by poorly conceived and configured spam filters.

It appears that many ISP’s (Internet Service Providers) are responding to complaints by their customers (about the torrent of spam they receive) by modifying and reconfiguring their spam filtering technology.

Unfortunately, these responses have not been well thought out and implemented.

I will provide a couple of examples but first I need to define some terms:

  • User PC – the personal computer used by an end-user to send or receive an email
  • Email Client – the software on the User PC used to compose and read email
  • Email Server – the server used by multiple users to handle both incoming and outgoing emails
  • ISP – a provider of internet connectivity to individuals and small businesses (includes big phone companies like Verizon, big cable TV operators like Comcast, and smaller local providers).
  • Spammer – the bad guys, typically using someone else’s hijacked PC’s or servers to broadcast thousands of undesirable junk emails to huge lists of email addresses

Example #1

I recently sent an email to a customer (an firm of architects) and had it bounced back to me as spam by the firm’s ISP. In this case the ISP was small, local outfit but a lot of the big guys are doing the same thing.

I created the email on my Windows XP computer using my email client (Mozilla Thunderbird). My email client is configured to use as the “From” address. It is also configured to send email via an email server provided by the hosting service I use to host This email server has a name along the lines of

Why was my legitimate email bounced back to me? The local ISP analyzed the header information of my email and found that the email server I was using was not part of the same domain as my email address and decided that this meant my email was spam.

My “From” address was which had a different domain than the email server The email header also includes the numeric IP address of the originating SMTP email server which would also be associated with my hosting service rather than my domain.

Now, it is true that essentially all spam is sent from SMTP servers which are not associated with their purported “From” or “Reply-to” email addresses. But it is also true that the vast majority of small to medium size businesses and organizations do not have their own SMTP email servers. So this policy of blocking emails where the “From” domain is not associated with the originating email server means that a lot of legitimate emails are being blocked.

In this particular instance, I called up my customer on the phone and explained the situation and asked for his fax number… And then I faxed him what I would have otherwise emailed.

Note that this means that this firm of architects is having some portion of its legitimate incoming email blocked. If the sender is not that motivated, he or she may just shrug and “walk away” and some potential business is lost.

The big email providers such as Yahoo, MSN/Hotmail, and Google/GMail also follow this practice. They don’t block unassociated emails but they do automatically put them in the end-user’s spam or bulk folder.

SPF Record

There is a partial work-around but it’s a little complicated and very few small or medium size businesses know enough to apply it.

The partial work around is called the SPF Record. SPF stands for Sender Policy Framework and you can find out more about at But in essence, the SPF record is part of a domain’s registration record and it provides a list of domains and servers that can legitimately send email associated with that domain.

So I set up an SPF Record that included the email server information for my hosting provider’s email server (and a third party email server I use). I waited a few hours and then sent test emails to accounts I have on Yahoo, MSN, and GMail… And it worked. None treated my emails as spam.

I then sent a test email to my architect customer and it also got through fine.

To summarize… Once the SPF record is implemented, an ISP (such as Yahoo) receiving an email purported to be from can check the domain records for and confirm that the smtp server I used was authorized to send emails.

Example #2

My hosting service is very good about ensuring that their servers are not used for spamming. This is critical because each of their servers hosts dozens of domains and they all share a single email server. If any one of those domains is sending spam (either deliberately or because they were hacked) then all mail from that email server gets blocked or labeled as spam by the big ISP’s.

But recently a new problem has arisen with one of the larger ISP’s (Comcast).

The scenario is that someone hosting their domain with the hosting service decides to forward their email (sent to, for example, to an email address they have on Comcast (i.e. Presumably Comcast is the ISP for either their small business or their home computer.

This should not be a problem but it is… Because Comcast views any spam that is being forwarded as being generated by the forwarding server and Comcast then blocks said forwarding server. This is causing such a problem that the hosting service has banned anyone from forwarding email to Comcast addresses. This is, of course, hurting Comcast’s own customers… Some are finding that they are not allowed to forward emails to their own comcast email accounts… And even more are having legitimate emails sent to them blocked.

I have a number of customers with comcast addresses, and I now send emails to them via my GMail account. That seems to work fine even though I am sure a lot of spam gets forwarded via GMail. Perhaps Comcast is scared of blocking emails from an entity as large as Google.

Which domain extension should I use for my site?

Monday, April 3rd, 2006

In general, businesses (in the US at least) should use the .com extension. Non-profit or political organizations usually use the .org extentions. Not surprisingly, the .gov, .mil, and .edu extensions are restricted. If you really want a particular website name (e.g. and the .com or .org versions are already taken then you might be able to register,,, or Or maybe you will have to settle for

What is the difference between all these domain extensions?

Wednesday, March 15th, 2006

When the Internet was first created by the US Department of Defense Advanced Research Projects Agency (ARPA) the only domain extensions were .gov (for US government sites), .edu (for educational institutions), and .mil (for US military sites). When the Internet was opened up to commercial and other users in the late 1980’s the .com (for commercial sites), .org (for organization sites), and .net (for network related sites) were created. Additional information on these and other “generic” domains can be found here. As the Internet and the World Wide Web has spread around the planet, the “non-generic” two letter country domain extensions were added. (For example, the BBC world news site is where UK stands for United Kingdom).

How does one register a new domain?

Friday, March 10th, 2006

Domain registration was opened up to commercial competition several years ago. There are now dozens of commercial domain registrars in the US and other countries around the world. Unfortunately the quality, reliability, and pricing varies considerably among the various domain registrars. We normally use Dotster ( and have found their cost and level of service to be quite good. A number of our customers use GoDaddy and we have found GoDaddy to be reliable and reasonably priced.

If you ask us to register your new domain, we would check to see if the name was available (i.e. no one else has previously registered it) and then we would arrange registration such that you and your organization are listed as the owner and ourselves as the technical contact. The registrar will typically charge around $15 per year and one can register for multiple years. The price may vary depending on what TLD (top level domain) you are registering. Examples of TLDs are .com, .org, .net, .info, .edu.

What is domain registration?

Tuesday, March 7th, 2006

Each website must have a unique domain name (e.g. and this name must be registered in order for it to be found by web browser over the Internet.

There is a master register (essentially an index) which contains the name, who owns that name, and the numerical IP address of the server (a computer) on which it resides. Copies of this master register are kept on hundreds of other servers (called domain name servers or DNS) around the world. It can take up to 72 hours for a new registration (or changes in an existing one) to propagate to all the DNS servers. In general, your local DNS servers are maintained by your ISP (Internet Service Provider). For example, we connect to the internet using Verizon DSL, so all our machines (and browsers) look to the Verizon DNS servers to find a target website.