On Tue, 14 Dec 2004 22:36:34 -0500, "Jim Fox" <(E-Mail Removed)>
wrote:
>Jeff Liebermann wrote:
>> In any case, 192.168.0.1 should work.
>It should work on the LAN side, assuming no configuration changes were made
>that would prevent it from working. But on the WAN side, in addition to
>entering whatever IP address it has, you have to add :8080 for port 8080.
>For example, 111.222.333.444:8080. I have two routers, with the WAN port of
>the WGR614 connected to a LAN port of my main router, and this allows me to
>access the WGR614 from that LAN, which is on a different subnet.
>
>But that raises the question: are two LANs involved? If the WGR614 is set
>to automatically received a DHCP address from a router on a first subnet
>(e.g., 192.168.0.1), then the WGR614 subnet might automatically be changed
>to 192.168.1.1. I haven't tried this myself, since I set a static IP
>address, but that is probably how it would work. (So in that case, he would
>have to access the WGR614 on 192.168.1.1, or whatever).
You have all the right buzzwords, but are apparently lacking in how
they are glued together to make a router. Let me try from the
beginning:
A router is a box that is designed to connect two dissimilar networks.
In this case, one network is the greater internet, also known as the
WAN (wide area network). The other network is your own network, known
as the LAN (local area network). Additional networks can also be
connected using static or dynamic routes, but we won't go there.
The basic requirement is that the WAN and LAN networks do not overlap.
Therefore, the LAN side of the router is usually assigned a Class C IP
address block of 255 addresses, such as 192.168.1.xxx. RFC-1918
allegedly insures that nobody on the greater internet uses
192.168.xxx.xxx for their internet connection.
On the WAN side of the router, you have a connection to the internet.
Your favorite ISP assigns you an IP address for the router, and a
gateway through which all packets *NOT* destined for 192.168.1.xxx get
to the ISP and then to the internet. This is called the routeing
table. The routers purpose in life is to connect devices on the LAN
side of the router to the WAN side using rules in this router table.
This is not a great time to explain how to decode a router table.
Connecting to the internet from any device on the LAN is fairly
simplistic. EVERYTHING goes through the ISP's default gateway IP
address and then to the internet. It doesn't matter what IP addresses
(except 192.168.1.xxx) or which IP port numbers 1-65535), they all go
to the internet via the default gateway. Computers and devices are
seperated using NAT (network address translation) and PAT (port
address translation as Cisco calls it) which seperate different
streams using port numbers.
However, coming in from the internet, we have a problem. Your router
has only one WAN IP address. However, there can be as many as 253
computahs on your LAN side. There's no easy way to connect to a
specific computah. For this we have "port redirection" which I don't
wanna burn time on right now.
Coming into the router configuration from the internet, one connects
to the WAN IP address of the router as assigned by the ISP. Coming
into the router configuration from the LAN, one uses the LAN side IP
address (usually 192.168.1.1). Both these addresses are the same
router, just different sides of the router.
From the LAN side, port 80 is usually used. That's not a problem
because the IP address used refers to exactly one device (the router).
However, coming in from the WAN presents a problem. If port
forwarding is enabled and configured, one has to specifically select a
port number that isn't already being used. Port 80 is highly likely
to be used if port forwarding is configured to point to a web server
on the LAN. This is how you run your own web server, by redirecting
the WAN side port 80 to a specific computah on the LAN. So, a
different port is necessary. It can be any port number but for some
odd reason, the cheapo router manufactories limit the choice to 1 or
three port numbers. Usually 8080 is on top of the list, so it gets
selected. Normally WAN side configuration access is disabled to
prevent hackers like me from taking over your router.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice
http://www.LearnByDestroying.com
#
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(E-Mail Removed) AE6KS
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