Monthly Archives: August 2008

Color blindness and accessibility

Computing, English, Internet

color blindness testIn an effort to meet accessibility requirements, I was looking for tools to check whether users with a variety of color blindness conditions can actually use our websites. Posters and brochures can already be difficult to read for color blind people. On web sites another dimension is added to this problem because certain features may be rendered useless by choosing a bad color palette. Colored links for example, if not underlined, may not be seen as links because they appear to be of the same color as all other text. Continue reading →

Email Address Validation Tool

Computing
I have been doing do a lot of email marketing lately. Our email marketing service does a pretty good job at removing records with an invalid email address from the imported data set. However, some invalid addresses still slip through and cause unnecessary bounces and license costs. We therefore need to correct or remove all invalid addresses before we import them. Some can be easily corrected without involving the subscriber, like

someone@hotmail
someone @ yahoo.com
someone@gmail.cmo

Others can be removed from the subscriber list because they originate from fake subscriptions, like test@justtesting.

I was looking for an online tool to clean up an email address list but could only find tools that process one address at a time. So I read RFC 3696 to learn more about valid email address formats and wrote my own. The tool does email format checks for most of the RFC requirements. It also queries the email domain’s DNS server to look for MX and A records.

Enter email addresses into this box. Unless you have the admin password, no more than 100 will be processed at a time (20 if DNS checks are requested) and your IP address will be recorded, so spammers must not use this to validate their address lists :-). If you abuse the tool, your IP will be blocked automatically.

A future version of this tool will work with the name@[IP address] address format and also telnet into port 25 of the email server to see whether there is a live SMTP service running.

DNS tests on domains?

Admin password
(only needed if more than 100 addresses, or more than 20 with DNS test):

Continue reading →