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Date:      Mon, 30 Apr 2001 23:28:12 -0500 (CDT)
From:      Nick Rogness <nick@rogness.net>
To:        Court Idstrom <court@idstrom.com>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: Multiple External IPs and NAT
Message-ID:  <Pine.BSF.4.21.0104302308260.83981-100000@cody.jharris.com>
In-Reply-To: <NBEKIMFDNBIOPIMKAMLKEEACCIAA.court@idstrom.com>

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On Mon, 30 Apr 2001, Court Idstrom wrote:

> Hi -
> 

> We're looking to expand our bandwidth here by using multiple DSL
> lines. They will both have a single dynamic ip address. I would like
> to use NAT for this, but I'm not sure how to set it up. Doing it with
> the single IP is easy. I want to keep all of the internal addresses in
> the same subnet, but if it's not possible otherwise I can split them
> (but they'll need to remain on the same hub).

	It's possible to keep the same address space internally.  However,
	you will not be able to load-balance across these 2 DSL
	connections unless you are route peering with these DSL
	providers...which I seriously doubt.  


	Is the second DSL connection from the same provider?  Is it
	business class DSL (or whatever they call it).  You could talk to
	them about this.

	Let me restate that...you can not equal cost load balance.  I
	guess you could pseudo load balance by selecting half of all
	destination IP's are through 1 DSL provider and the other half
	are through the other DSL connection...not very optimal.

	There was also talk about using the ipfw probability in use with
	load-balancing but I never got around to looking it over.

	You *CAN*, however, use the second DSL line for redundancy.

> 
> I am going to need to use 2 external NICs and 1 internal card, and I
> haven't seen any information regarding using 2 NICs.

>Will I need to run two instances of NATd?

	Yes, you will...one for each interface.

	First, run the normal nat:

	root# natd -n $int1
	root# ipfw add divert natd ip from any to any via $int1

	The second natd:

	root# grep nat /etc/services
	natd            8668/divert # Network Address Translation
	natd2           8669/divert # Network Address Translation

	root# natd -p 8669 -n $int2
	root# ipfw add divert natd2 ip from any to any via $int2

	This should get you on your feet. How you handle redundancy is up
	to you...which we can continue once you have the above setup and
	working.


Nick Rogness <nick@rogness.net>
 - Keep on Routing in a Free World...
  "FreeBSD: The Power to Serve!"




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