What is blocking port 80?

[Ken Schweigert]

On Tue, 21 Sep 2004 11:01:36 -0600, camroe@telusplanet.net
<camroe@telusplanet.net> wrote:
> Hi all,
> 
> So I'm trying to run an Apache web server on my YDL.
> I'm running Apache 2.0.50 on YellowDog Linux (YDL) Release 3.0, Kernel
> version 2.4.22-2f. I am running it behind a D-Link DSL firewall/router
> DI-601. My YDL machine is assigned a local IP 192.168.1.5.
> I was screwing around with the port forwarding but wasn't having any luck so
> I put the YDL in a DMZ (i.e. WAN has ALL access to this machine) I can FTP
> and Telnet to it using the dynamically assigned ISP IP address of the router
> (199.21.148.227 ... and no that's not the real address :)  )
> 
> The problem is that when I  browse to the address (199.21.148.227) I expect
> to get the Apache test page, but I get 'The connection was refused when
> attempting to contact 199.21.148.227'. I can brows to the 192.168.1.105 from
> another machine on my local home network, but I can't get to it from an
> external machine - i.e. at the office. I've tried both netscape and IE, as
> well as tried to telnet to port 80 (tenet 199.21.148.227 80), but still get
> connection refused. I've checked the Apache logs and there are no access_log
> entries or error_log entries. That there are no entries confirms my belief
> that Apache never gets the request and that port 80 is being blocked from
> external access.
> Thanks for your help!!!
> 
> Cam

Two things to check:  

1) check your router - it may be that you don't have port forwarding
configured correctly

2) check your ISP's Acceptable Use Policy - some ISPs don't
allow/block connections to low level ports, specifically SMTP and
HTTP.  Some don't want you send email from your machine, like spammers
do, or make money hosting websites they should be making money doing.

-ken