Re: [tlug] routers and port forwarding

[Al Hoang <hoanga@example.com>]

Evening,

Charles Muller wrote:
> My Bittorrent downloads have recently come to a virtual halt for 
> reasons I don't quite understand,
> [snip]
> I am hooked up with optic fiber via e-Mansion, which is basically an 
> ISP foisted on/provided to people who buy new manshons in Tokyo. 
> Obviously I have no router in my own room--I have a wall outlet that I 
> plug into. But am I right in guessing that there must be a router 
> either somewhere in my building, or somewhere else nearby, to which 
> this port forwarding might be applicable?
   Bittorrent really desires having incoming connections to make file 
transfers work.  If incoming connections are blocked I've noticed this 
can make Bittorrent be a bit sluggish.
   Before we start opening ports or anything else, here are some 
questions and reasons for the questions that I think might illuminate 
your networking situation. 
1. Is the IP address you're receiving when you plug in your PC to the 
wall outlet a global IP address or a private address?  [1]
   If you're getting a private address then this means there is a 
router / firewall somewhere upstream that is multiplexing people's 
connections and this will require 'port forwarding' however this is not 
in your hands anymore.  If it's not a private address...
2. Who exactly is the ISP provider?  
   I've seen a similar setup as your hikari fiber setup.  When I read 
the fine print, it was Usen who was the actual ISP.   Once you know the 
ISP you can look up the particular service you have and try to extract 
as much information from services offered.  I believe another TLUGer had 
a problem with very slow bittorrent connections and it turned out that 
his ISP automatically did port blocking of many ports however there was 
a web form to request an opt out.
3. Are FTP connections slow? 
   Try downloading a Linux ISO from a Japanese mirror.  I don't expect 
this to be slow but might as well check just to be sure.
4. If you enable a web server such as Apache can you connect to it from 
an outside machine?
   If you can't then you know your ISP is blocking ports or you have a 
private address.  If it isn't, you at least have a global IP although 
your ISP still MIGHT be blocking ports.

Hope that helps as a starter,
Alain

[1] RFC 1918 Address allocation for Private Internet