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From Thomas Bolioli <i...@terranovum.com>
Subject Re: [users@httpd] apache server 2.0.43
Date Fri, 10 Jan 2003 19:42:04 GMT
It depends on how your ISP's routers are configured but it may be that 
your ISP is doing more than just filtering. They may also be proxying. 
Consider the following:
Your ISP is going to filter port 80 upstream from you (it is not 
efficient to do this close to the modem for management purposes). May be 
two, three or more hops (routing points) away from your cable modem. 
Since your two cable modems are part of the same network the router down 
the street (one hop away) does not send it further since that is what 
routers are supposed to do (route data efficiently). Therefore the 
filtering never happens.
As for the ip v. DNS issue. That is not as clear to me and may involve 
the fact that most cable ISPs proxy http requests as well (RCN, AT&T and 
AOL for sure). It is possible that the proxy is on the up stream side of 
the filter (KIM the cable modem may be aware of the proxy) and can not 
get access to your machine to serve the request back to you. The 
difference in responses may be because http requests sent with no host 
header may not be proxied while those with host headers are??? HTTP/1.0 
v HTTP/1.1??? Remember that I suggested that the cable modem may be 
aware of the proxy. Some router or network component in the system does 
since proxies are selective in what they process (ie; port 80 requests 
only, no ssl requests, things with no cacheing rules applied) and those 
decisions can be made in a router and not by the proxy. ie; you make a 
request, an upstream router decides if it fit's a rule that makes it a 
proxiable request and it redirects that connection to the proxy instead 
of straight ahead to the end recipient.
I do not know how proxies and routers are built these days but they 
usually are highly configurable and rule based. People, not always 
trained, make the rules and there is where logic generally goes out the 
window. ;-)  
Hope this helps although I realize it doesn't fully solve your dilemma.
Good luck,
Tom
PS: I can see neither address from my locale. Also, this is a networking 
issue that has gone beyond the scope of this for sure.

David Jones wrote:

>ok can someone please explaine this one to me
>my isp say they are filtering port 80 and i have 3 computers 2 of them are
>on a router
>and the other one  on a diffrent connection but all on the same ISP
>2 cable modems
>one for the 2 cpu's on the router
>and one by its self
>i have apache running on one of the two on the router and can see the server
>pages on both computers on the router
>and... here is the funny part
>i can go to my other computer on the other side of the room and pull it up
>by typing this
>and only this ---->  http://66.169.74.233
>but not able to with this---> http://jonespc.no-ip.biz
>can someone help here
>could it be that all 3 computers are networked together via broadband cable
>line within my house
>
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