My Experience with Anti-Spam Mail Measures
One Monday afternoon when I came back to the office from a business trip, I was trapped by my PC: “I cannot send any e-mails!” I restarted my PC several times, but the situation was the same. I kept receiving emails, but could not send any emails at all. I thought, Okay, maybe it’s a problem with Microsoft Outlook. Then I tried to send an email using another e-mailer, namely Thunderbird; but I could not send any emails using this either. Internet connections and webmail systems were functioning well, however. So, I called up the hosting company, our office manager, and an anti-virus software company to find out what had caused the problem. After spending almost a whole day investigating, I finally found out the cause of the problem:
Outbound Port 25 Blocking.
Move Towards Blocking Port 25
Since late last year, major Japanese Internet service providers (ISPs) and mobile telecommunication carriers have begun blocking Port 25 as part of anti-spam e-mail measures. Port 25 is the channel often used for transmitting emails to a server, and Port 25 blocking was one of the recommendations made by the Japan Email Anti-Abuse Group (JEAG) in 2006 to cut down the number of spam e-mails.
Impact on Users of Anti-Spam E-mail Measures
Port 25 blocking reduces spam emails, but it also blocks non-spam emails. Some users learn about Port 25 blocking for the first time when they encounter a problem with sending outbound emails. Many ISPs have prepared Port 587 as a substitute for Port 25. However, some users are not aware of the change in settings made by ISPs and they spend a lot of time trying to figure out how they can send email.
There are other anti-spam measures that make consumers annoyed. For instance, under the Japanese anti-spam law, companies have to obtain permission from customers before sending them promotional emails. The terms and conditions customers have to read and agree to are often too lengthy to read. Whenever I buy household goods from a Japanese website, I am always asked to read 1 or 2 pages of terms and conditions, and to state whether I agree to receive promotional emails or not. I should appreciate such anti-spam measures which help to prevent annoying emails, but I am sometimes annoyed by the process I must go through.
April 30 2008 08:37 am | Technology and Weekly Articles
Amir on 01 May 2008 at 1:52 AM #
ISP are trying to cope with the outbound spam problem, usually caused by zombies, by blocking port 25.
It is not just in Japan, i have talked to ISP’s all around the world and this is a method some of them are applying.
Unfortunately, this method increases the false positive as well, but i guess that as long as the customers won’t put pressure on the ISP, it will consider for them a good solution.
Noriko on 01 May 2008 at 10:47 AM #
Yes, I also realize that ISPs outside Japan start blocking port 25.
I believe customers should pressure on the ISPs to take account of usability as well as to offer better solutions.
Greg L. on 01 May 2008 at 11:13 PM #
You can normally get away with changing the port to 26 - many hosting providers allow you to use this for SMTP.
Noriko on 02 May 2008 at 4:10 PM #
I am not sure how many ISPs use Port 26… JEAG recommends to use Port 587 because it is defined by RFC2476.
Ken on 19 May 2008 at 11:40 PM #
Definitely what is most frustrating is when the ISP doesn’t tell anyone that they’ve blocked port 25. Now we just add that to the list of what might be wrong!
What I’ve seen that’s even worse is limiting people to sending only 10 emails in 10 seconds - without telling them! This can be a disaster if you’re running an email marketing list.