[colug-432] modems routers switches Oh my!

Rob Funk rfunk at funknet.net
Sun Aug 7 20:40:48 EDT 2011

On Sunday, August 07, 2011 01:04:27 pm Vince Herried wrote:
> She wants to dump her router and buy
> one with more ports.  At present
> no WIFI is involved.  I suggested a switch or even a hub rather than
> another router.

Good recommendation.

> So what is going on here,  I have always thought that having two routers
> in series was bad!

Two routers in series isn't bad, but both of them doing NAT is less than 
ideal. On the other hand, as IPv4 addresses run low, ISPs are more likely to 
set up their customers behind multiple NAT layers anyway.

> What kind of real life issues are there when you have two NATs going on
> at the same time.
> Obviously it can't be as bad as I thought, because it has been running
> that way for years.

The most common problem I've run into with multiple layers of NAT is in 
situations where the outside needs to initiate a connection (server or p2p 
scenarios). These days many routers and software systems will work that out 
with UPNP, but only to one NAT layer. I ended up digging into my DSL box's 
settings to switch it to bridging mode in order to avoid this problem.

> Do manufacturers continue to make modem/routers with a single port which
> seems to encourage this misuse?

I don't see it as a bad thing to have a modem or a router with one internal 
port. People just need to understnd that they need a switch (not a router) 
if they have more than one wire to connect.

A big part of the problem is that people don't understand the differences 
between a router and a switch and a wifi access point and a modem, since 
it's common for one box to do multiple things.

==============================|   "A microscope locked in on one point
 Rob Funk <rfunk at funknet.net> |Never sees what kind of room that it's in"
 http://www.funknet.net/rfunk |    -- Chris Mars, "Stuck in Rewind"

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