[BC] Barix Question

[RichardBJohnson at comcast.net]

I don't think you know what the real IP address is when using any commercial ISP with DHCP. The address that you can see, i.e., the address that your modem picked up, is itself a local address because you are a node on a node on a node,... etc.

The reason why you can't ping that address from somewhere else is not because ICMP has been turned off, but because that address isn't routed. It isn't routed because there are literally thousands of the same addresses. See http://www.jpsdomain.org/networking/nat.html for more information.

In addition, my DSL modem at my office often picks up 71.255.161.190. Even though it is running right now, it can't be pinged from my home which has Comcast cable, but can sometimes be pinged from another Verizon DSL account. Here is what WHOIS says about that address.

Data from whois.arin.net:
 	 
OrgName	Verizon Internet Services Inc.
OrgID	VRIS
Address	1880 Campus Commons Dr
City	Reston
StateProv	VA
PostalCode	20191
Country	US
 	 
NetRange	71.255.160.0 - 71.255.255.255
CIDR	71.255.160.0/19, 71.255.192.0/18
NetName	VIS-BLOCK
NetHandle	NET-71-255-160-0-1
Parent	NET-71-0-0-0-0
NetType	Direct Allocation
NameServer	NS1.VERIZON.NET
NameServer	NS3.VERIZON.NET
NameServer	NS2.VERIZON.NET
NameServer	NS4.VERIZON.NET
NameServer	NS5.VERIZON.NET
NameServer	NS6.VERIZON.NET
Comment	
RegDate	2004-11-09
Updated	2009-10-14
 	 
OrgAbuseHandle	VISAB-ARIN
OrgAbuseName	VIS Abuse
OrgAbusePhone	+1-214-513-6711
OrgAbuseEmail	security at verizon.net
 	 
OrgTechHandle	ZV20-ARIN
OrgTechName	Verizon Internet Services
OrgTechPhone	800-243-6994
OrgTechEmail	IPNMC at gnilink.net
 	 

This means that for peer-to-peer communications through the Internet, one needs to connect through a router with an IP address that is resolvable to both peers. For a one way connection, one machine needs a static address. For both ways, both machines need a static address. Note that once connected, DATA can flow in both directions.

This is not the same as a LAN (local area network). On a LAN, even if you don't have local name-resolution, you can search for your peer, simply by trying to connect with everything on your LAN, with your private port, until the connection succeeds. Such would never be successful on the Internet because the intermediate addresses are not routed.

Assuming that you had a static address, you could write a program that runs on the machine with the static address that would allow connections from many clients. The program could then route packets between clients, using the computer's routing capabilities, without further involvement by the program. Basically, a client wanting to connect to his peer (perhaps a Barix Box) would first connect with the server on its listening port and exchange pleasantries (private information that identifies its peer). This information would be retained, and once the peer did the same thing, the program would modify the computer's routing tables so that the peers could stream data between them. Unfortunately, this has its cost. The amount of streaming data on the link would be doubled, because the data would come to the router and then be sent from the router using the same circuit.

Cheers,
Richard B. Johnson
Book: http://www.AbominableFirebug.com/

----- Original Message -----
From: "Broadcast List USER" <Broadcast at fetrow.org>

While I have found static IP addresses to be reasonably priced, if you  
can do the service for less, that is yet another plus.  (I have also  
treated my cable and DLS home circuits as static as they very rarely  
change.  Even if I turn off the "modem" for 10s of minutes, I  
frequently get the same IP address.  I know they used to rotate them  
from time to time, and I assume they still do, but not frequently.  Of  
course, I would never depend on the DHCP not changing my IP address  
for anything even close to important.)