Email Blocking

"550 5.0.0. Server ... blocked as possible open relay"

Explanation: This error message means that an email that you sent, or an email that was forged to appear as if you had sent it, matched a filter on Alaska Communications Systems' email servers. These filters were put in place to control the quantity of unsolicited commercial email ("UCE" or "spam") sent to our customers. There are a number of reasons why a particular server or host may be included in our filter:

• Open Relays:
  Typically, a mail server is configured to allow anyone to send email to local recipients, or to allow senders on that same network to send to anyone on the Internet. An "Open Relay" is a server that has been misconfigured in such a way that it allows anyone on the Internet to relay messages to anyone else on the Internet. This is bad because it allows spammers to relay UCE through the server with anonymity. In a properly configured mail server, the mail administrator can identify and take steps such as suspending or terminating the account of someone who abuses the email service.
  
• Open Proxies:
  An "Open Proxy" is much like an open relay in that it allows spammers to send emails anonymously. However, while an open relay "listens" on the port used for e-mail traffic, an open proxy "listens" upon other ports, such as those used for web browsing. Also, unlike an open relay, an open proxy can be used for many other purposes besides relaying email--for example, anonymous web browsing, port scanning, defacing web sites or other illegal activities.
  
• Insecure or Improperly Secured FormMail Scripts:
  FormMail is a script that allows visitors to a web site to send questions, feedback, or other communications to the owner or maintainer of that web site. Unfortunately, older versions of FormMail had security flaws that allowed spammers to send unsolicited e-mails through the web server that hosted the FormMail script.
  
• Virus or Trojan Activity:
  Many viruses, trojans and other malware have been written to operate in much the same way as open relays and open proxies, allowing spammers to relay UCE through an unsuspecting victim's computer. Computers compromised in this way are called "zombies" and are currently one of the biggest problems faced by Internet Service Providers today.
  
• Deliberate Spamming:
  Finally, there are those miscreants who abuse email services intentionally by sending unsolicited commercial or bulk emails to literally thousands of recipients. Such practices place an extreme load upon the mail servers through which the offending emails are sent, and clutter the recipients' inboxes. ACS, like many other ISP's, blacklists any known or suspected spam sources in order to maintain our customers' good will and protect our mail servers.

If you wish to be removed from the filters on Alaska Communications Systems' email servers, you must identify how the offending email was sent through your server or computer, take action to resolve the problem, and contact ACS' mail server administrators to request that we remove your server(s) from our filters. While ACS will evaluate all requests for removal, removal is at ACS' sole discretion, and we are not under any obligation to comply with your request. You may reach ACS via email at either abuse@acsalaska.net or postmaster@acsalaska.net.