What is bad about double/triple NAT for regular browsing / streaming of videos?

[slicksilver]

I have three wireless routers in three floors at our family home. 2nd router to the first router via the Lan port on the 1st router to the Wan port of the 2nd router one. Same connections for the 2nd and 3rd router. Is there any disadvantage of doing this as opposed to a single NAT?

Thanks in advance for any help you are able to provide.

 

[JackMDS]

If you need LAN then you have three Independent LANs that would connect only Outward toward the Modem.

Advantage? Read this - Network Segregation, http://www.ezlan.net/shield.html

One LAN - Using Wireless Routers (or Modem/Wireless Router) as a Switch with an Access Point - http://www.ezlan.net/router_AP.html

 

[dave_the_nerd]

Laggier. A slow router can bottleneck a faster one. Can interfere with internet gaming and/or bit torrent for sure. Will probably get into a situation where local LAN services like backups or printers don't work because client A can ping B but B can't ping A. That sort of thing.

It can work - if you do it right, you can NAT the NATT'd NAT NAT all day long and everything's fine. But most people aren't good enough at managing and configuring a router/network to make it work well for all involved, so for home users it's a violation of the KISS principle.

 

[RLGL]

Laggier. A slow router can bottleneck a faster one. Can interfere with internet gaming and/or bit torrent for sure. Will probably get into a situation where local LAN services like backups or printers don't work because client A can ping B but B can't ping A. That sort of thing.

It can work - if you do it right, you can NAT the NATT'd NAT NAT all day long and everything's fine. But most people aren't good enough at managing and configuring a router/network to make it work well for all involved, so for home users it's a violation of the KISS principle.

This has always been a question for me:
On DSL, I have NAT in the modem with this message:
NAT
Do not disable NAT unless instructed to do so by your ISP. Turning off NAT will open your Broadband Modem to outside intrusion, creating a security risk.

My router an Asus RT N66R also has Nat enabled. Every time I turn it off I loose my internet connection.
Should I be turning the NAT off in the modem?

 

[Mushkins]

This has always been a question for me:
On DSL, I have NAT in the modem with this message:
NAT
Do not disable NAT unless instructed to do so by your ISP. Turning off NAT will open your Broadband Modem to outside intrusion, creating a security risk.

My router an Asus RT N66R also has Nat enabled. Every time I turn it off I loose my internet connection.
Should I be turning the NAT off in the modem?

No. You want NAT enabled for the router connected to the modem. Anything past that you want to disable NAT and keep it on the same network. Single NAT is a good thing.

You should flatten your existing network to avoid double/triple NAT problems. Basically leave your first Router alone and configure additional routers as detailed in the following article.

How do I use a Wireless Cable/DSL Router as a Switch with an Access Point:
http://www.ezlan.net/router_AP.html

 

[RLGL]

No. You want NAT enabled for the router connected to the modem. Single NAT is a good thing.

http://www.ezlan.net/router_AP.html

What is the purpose of having NAT enabled in both the modem and the router?

The modem has routing capability but I am not using it or the wireless functions

 

[Mushkins]

What is the purpose of having NAT enabled in both the modem and the router?

The modem has routing capability but I am not using it or the wireless functions

There isn't one, that's a double NAT situation. If it's a modem/router combo device, then it's technically your edge router unless you reconfigure it as a network bridge. A consumer grade router in its plug and play state *is* routing, you'd need to disable those functions if you don't want it to be a router as per the link.

NAT should only be enabled on the one router that is actually doing routing and acting as your edge device.

 

[RLGL]

NAT should only be enabled on the one router that is actually doing routing and acting as your edge device.

There is nothing in the modem about a network bridge. Is there any harm in turning off the NAT in the modem?
Or should I leave it the way it is at the present?

 

[JackMDS]

There is nothing in the modem about a network bridge. Is there any harm in turning off the NAT in the modem?

At the Moment that there is NAT it is Not A Modem, it is a Combo Modem/Router.

It is Not the words on the plastic Box that really defines Devices, the Electrical Circuit are the Functional reality.

Many Modem/Routers can not work as a Bridge (Modem only), it is Not just a matter of switching Off the NAT.

Why it is so? It is just a Manipulatory self Interest Buisness/Marketting/ Support convenience decision of the ISP providing the Device.

 

[RLGL]

Thanks Guys
Dave
Stillwater,MN

 

[Red Squirrel]

It will add some overhead and extra complexity especially when it comes to port forwarding, but if you know what you're doing, it's not really THAT bad. It seems now most ISPs force you to use their router due to the way they mux the TV, phone and internet so sometimes you have no choice if you already have your own, better router/firewall. For example there is no way I wanted to replace my Pfsense with a crappy SOHO router when I got fibre internet which required to use their Actiontec which is setup to handle the connectivity. Though someone happened to write a custom firmware for an Asus router which allows to setup the internet as passthrough, so I ended up doing that.

Now if your goal is to create separate LANs, your best bet is vlans and a firewall like pfsense that can do inter-vlan routing/rules. But double NAT with multiple routers behind a NAT will work.

I'd be curious to setup like a 100 level NAT to see what kind of performance/latency you get, though. Could make for a funny experiment.