[NTLUG:Discuss] how do i know if port 80 was blocked?

[Patrick Parks]

There is also a program called iptraf that you can run in a terminal
window on the machine with the web server that will show you all of the
incoming traffic on the ehternet or ppp connection.


On Fri, 2003-01-03 at 14:36, m m wrote:
> Thanks you all for the reply.
> I am sorry that I should ask this question as:
> 
> How do I know if at&t block incomming http request to/for the ip 12.237.x.x?
> 
> the problem is the I have setup a web server, and just don't work (it worked 
> before I change cable modem, of course I registered the new MAC address). I 
> have heard that the at&t block the port 80 on some area. I wonder my web 
> site don't work because they block port 80 on my ip.
> 
> thanks.
> 
> 
> 
> 
> 
> >From: MadHat <madhat at unspecific.com>
> >Reply-To: discuss at ntlug.org
> >To: NTLUG-Discuss <discuss at ntlug.org>
> >Subject: Re: [NTLUG:Discuss] how do i know if port 80 was blocked?
> >Date: 03 Jan 2003 14:20:44 -0600
> >
> >On Fri, 2003-01-03 at 14:05, Philip Stetz wrote:
> > > --- m m <llliiilll at hotmail.com> wrote:
> > > >
> > > > Hi all:
> > > > Is there any to find out if the port 80 was blocked?
> > > > IP 12.237.x.x from at&t
> > > >
> > > > thanks
> > > >
> > >
> > > you can use nmap to do a port scan on that ip.  some
> > > sys admins may frown upon that though :)
> >
> >Depending on how the router/firewall is configured, it may or may not
> >tell.  If it just drops the packets, you can't tell if it being blocked,
> >or his machine just doesn't have anything on port 80.
> >
> >If the router sends an ICMP prohibited message, nmap will show filtered,
> >but that is not always accurate, as some timeouts will show filtered as
> >well.
> >
> >If the router sends a reset it will just show closed, even though it may
> >be blocked.
> >
> >To be 100% sure, start up a sniffer on the 12.237.x.x machine and then
> >telnet to port 80 to it from a machine on a different network and look
> >for the traffic in the sniffer.  If it shows up, it isn't blocked.  Of
> >course you can still use nmap, but that is overkill.  You can also use a
> >plethora of other tools like netcat or any other port scanner, but
> >telnet is easy and will do the trick.
> >
> >
> >--
> >MadHat at Unspecific.com
> >`But I don't want to go among mad people,' Alice remarked.
> >`Oh, you can't help that,' said the Cat: `we're all mad here...'
> >    -- Lewis Carroll - _Alice's_Adventures_in_Wonderland_
> >
> >_______________________________________________
> >https://ntlug.org/mailman/listinfo/dis
> 
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-- 
Patrick Parks
patrick at patrickparks.com
(972) 416-9927 Home
(469) 939-6460 Mobile
"May the SOURCE be with GNU"
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