XPost: alt.comp.software.thunderbird   
   From: nospam@needed.invalid   
      
   On Mon, 2/23/2026 8:47 AM, R.Wieser wrote:   
   > Paul,   
   >   
   >> The protocol is blocked by the ISP DPI box.   
   >   
   > I doubt it.   It would mean that noone can use another email server than the   
   > one the ISP offers - if it offers one to begin with that is.   
   >   
   > Regards,   
   > Rudy Wieser   
   >   
   >   
      
   I believe who is blocked, is anyone from outside an ISP   
   attempting to use an "open" SMTP implemented inside the ISP.   
   I can set up an SMTP server on Port 25, and if you try to   
   reach my 1.2.3.4:25 SMTP server, you would be blocked from doing so.   
   It's also quite possible, that my next door neighbour using my   
   ISP as well, could not reach my SMTP server on Port 25.   
   If I move my server to 1.2.3.4:1025, it is the protocol   
   which is effectively blocked, and any port number observed   
   to be carrying inbound SMTP gets blocked.   
      
   If you have a business account, the rules are different.   
   You're not supposed to be running *any* server on a $39.95 per   
   month consumer plan.   
      
   And the funny part is, when you phone up tech support and   
   ask them if there is any blocking or filtering going on,   
   the entry level tech support will vehemently deny they block   
   things. When every ISP tends to have the same rule set.   
      
   If any ISP were to start emitting spam email traffic,   
   there are tables of spammers available for other ISPs to block,   
   so you would soon find that your ability to "handle (spam) mail   
   successfully" was blocked.   
      
   If you read the article, you can see the technical capabilities   
   are pretty amazing. And by implementing this at the edge of the   
   network, and using thousands of DPI boxes, you can do complex   
   things at scale.   
      
     https://en.wikipedia.org/wiki/Deep_packet_inspection   
      
   Blocking isn't done just with routers, the DPI boxes are   
   much more flexible about it.   
      
   If there is a naughty thing you should not be doing,   
   the ISP has a filter for that.   
      
        Paul   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)