[Tfug] Comcast to start blocking port 25?

[Jerry S.]

Hello tfug,

  Cox is already doing this and has been for a while.  This really
  isn't something new, just new for comcast.

  jer

Friday, June 11, 2004, 8:53:38 AM, you wrote:

ASF> This could be a real PITA for many of us.  OTOH some estimates suggest
ASF> that most (80%?) of spam is spread through zombie PCs on on broadband
ASF> connections.  This could help there.

ASF> http://news.com.com/2102-1038_3-5230615.html?tag=st.util.print
ASF> ------- Included Stuff Follows -------
ASF> Comcast takes hard line against spam
ASF>  By Jim Hu
ASF>  Staff Writer, CNET News.com
ASF>  http://news.com.com/2100-1038-5230615.html
ASF>  Story last modified June 10, 2004, 12:56 PM PDT

ASF>   Comcast, the nation's largest broadband Internet
ASF>   service, this week began selectively blocking a network
ASF>   loophole commonly exploited by spammers. 

ASF>   The cable giant, whose broadband Internet service has
ASF>   more than 5.7 million subscribers, said it will block
ASF>   what's known as "port 25" for accounts suspected of
ASF>   sending mass amounts of unsolicited e-mail. The company
ASF>   will implement blocks based on subscriber accounts with
ASF>   the most outbound activity. 

ASF>   Port 25 is a gateway that most computers use to send
ASF>   e-mail. That's because a technical specification called
ASF>   SMTP (Simple Mail Transfer Protocol), which lets people
ASF>   send and receive e-mail, operates on the port. 

ASF>   "We are singling out spammers on our network and
ASF>   blocking port 25," said Mitch Bowling, Comcast's vice
ASF>   president of operations. "We don't think it's the right
ASF>   approach to blanket port 25. The right approach is to
ASF>   seek out people who are spamming our network and
ASF>   others." 

ASF>   Comcast's port 25 blocks were first noticed in online
ASF>   public forums such as Broadbandreports.com. 

ASF>   The move comes amid mounting criticism against Comcast
ASF>   for not taking enough steps to thwart spam. Some
ASF>   measurement companies have highlighted Comcast as the
ASF>   greatest source of spam, most of it from subscribers who
ASF>   have no idea their computers have been transformed into
ASF>   spamming engines. Measurement site SenderBase estimated
ASF>   that 665 million e-mails a day come from Comcast
ASF>   domains, more than Yahoo and Time Warner Cable's Road
ASF>   Runner service combined. 

ASF>   In Comcast's defense, the company is not a direct source
ASF>   of unsolicited e-mail, but a convenient distribution
ASF>   point due to its size and speedy bandwidth. E-mail virus
ASF>   writers have targeted Comcast, among other broadband
ASF>   Internet service providers, to turn subscriber computers
ASF>   into spam "zombies" without their knowledge. 

ASF>   One Comcast engineer estimated the daily e-mail flow on
ASF>   the company's network at about 800 million messages,
ASF>   with only 100 million originating from its servers. The
ASF>   remaining 700 million came from zombie computers. 

ASF>   "This is a problem faced by many broadband providers,
ASF>   because as speeds increase, those broadband connections
ASF>   become a low-cost, high-efficiency delivery connection,"
ASF>   said Ray Everett-Church, chief privacy officer at
ASF>   TurnTide.com and an antispam advocate. 

ASF>   Blocking port 25 would prevent computers from sending
ASF>   e-mails from any non-Comcast SMTP server. This, in turn,
ASF>   would shut down people using Comcast's bandwidth to send
ASF>   spam from their own SMTP servers. It would also limit
ASF>   PCs acting as spam zombies from connecting to mail
ASF>   servers outside Comcast's network. 

ASF>   While many spammers use an open port 25 as a workaround,
ASF>   there are legitimate uses as well. More technically
ASF>   savvy subscribers and small businesses use the open port
ASF>   to connect to outside mail servers or to run their own
ASF>   SMTP servers. 

ASF>   "We have commercial customers that aren't spammers that
ASF>   we don't want to impact," Comcast's Bowling said. 

ASF>   Comcast is not the first ISP to take this measure. In
ASF>   fact, many service providers such as America Online and
ASF>   EarthLink have been doing this for many years. Other
ASF>   cable ISPs such as Cox Communications also have
ASF>   implemented port 25 blocks to fight spam. 

ASF>   For general subscribers who use Comcast as their primary
ASF>   e-mail account, the changes will go unnoticed, the
ASF>   company said. Already, Comcast has noticed a 20 percent
ASF>   reduction in spam since the blocks began and a 75
ASF>   percent decline in the past two months. 

ASF>   Whether this amounts to any significant reductions of
ASF>   spam on the Internet at large is unlikely, because there
ASF>   are other sources of junk e-mail overseas. But some
ASF>   people consider it to be a step in a seemingly hopeless
ASF>   war against spam. 

ASF>   "I don't care if Comcast customers are infected. I just
ASF>   care that the spam stops," wrote one
ASF>   BroadbandReports.com reader in the site's message board.
ASF> --------- Included Stuff Ends --------- 

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-- 
Best regards,
 Jerry

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