Dr. Zowie continues: "I use a regional ISP with otherwise-very-good policies. However, they seem to be intercepting
anything that comes from my home net on port 80, so that they can
``transparently'' cache web requests based on the payload of those
packets. The proxy seems to work rather well in most cases: I
never noticed it until I started using OpenNIC. Then I found that some web pages that should have
resolved OK through the OpenNIC system failed even though routing on
different ports worked OK.



"I did some experimentation using ``telnet'' on port 80
directly, and found that packets are being routed based only on
the payload regardless of the original destination address: I can (for
example) retrieve the Slashdot front page by using ``telnet
www.google.com 80'' and asking for "http://www.slashdot.org
http/1.1". The tech support folks seem to be stonewalling me: the
main contact tells me that the behavior is "not broken" even though it
clearly violates RFC
1812, the standard set of rules for IP routing.



"The practice of ``transparent'' proxy routing seems to be growing
more widespread. It appears to break the internet standard in a way
that works for most folks for now, but that breaks port 80 usage in general. Looking ahead, this breakage seems
like a growing nightmare waiting to happen. At the very least, I
expect more instances of my particular problem to appear as folks give up on the corporate hegemony of ICANN. More insidiously, transparent
proxy routers break the layered nature of the internet protocol and
restrict the flexibility that made it work in the first place. One would
hope that such proxies would at least act like routers when the fancier
proxying fails, but at least my ISP's doesn't. What about your ISP's?"