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c3750 nat

Posted on 2008-10-06
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Last Modified: 2012-05-05
Howdy,
  I currently have a cisco c3750 switch hooked up to a linksys router. What I'm wanting to do on the Cisco 3750 is to be able to nat. I want to have it so thatall  the linksys see's is 192.168.1.1 which i statically assigned to g1/0/1 which leads to the linksys router. Is this possible?

I enabled ip routing on the switch and turned g1/0/1 into a L3 port. But for some reason I cannot find the NAT command. Any Ideas?
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Question by:Paktusjet
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by:sstone55423
ID: 22655919
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by:sstone55423
ID: 22655922
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by:Paktusjet
ID: 22655979
I'm currently in that same situation as the link you provided.

Switch#config t
Switch(config)#ip nat ?
% Unrecognized command
Switch(config)#int fa0/1
Switch(config-if)#ip nat ?
% Unrecognized command

so how would I get NAT enabled? Many accepted solutions in that link stated that NAT was not supported by 3750's. Is that true or false? If so I need a work around.
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by:Paktusjet
ID: 22655988
I cannot configure the Linksys. What it has on it has to stay the same with no changes.
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sstone55423 earned 500 total points
ID: 22655998
http://www.tek-tips.com/viewthread.cfm?qid=1159588&page=1
 
AND
http://www.netxg.net/newsxg/2007/cisco-catalyst-3750-series-switch-quick-look/
Q. Is NAT supported? A. No. There are no plans to support NAT.
 
Well, I was wondering about that.  Sorry to point you the wrong way.
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by:Paktusjet
ID: 22656028
well can there be a work around? Is there any way that I can mask these IP addresses? This Linksys router does not know about the other networks on my backside. I need some way to wrap the IP's on my backside inside of one usable IP address if I cannot NAT.
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by:sstone55423
ID: 22656121
Well, just throw a router in there for basic NAT.  A Linksys WRT54G is good, or something like that.  There are other models without wireless that are like $29 at Best Buy.  It will do basic one to many NAT, and solve all of your problems.
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by:Paktusjet
ID: 22656126
well we have limited resources. All I have to work with is that 3750 and a Linksys router.
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by:sstone55423
ID: 22656127
I know, with the other linksys, that it will look a bit odd...but You seem to have some reason you don;t want the other Linksys to do the NAT.  SO...
Internet-->OLD Linksys-->New Linksys -->CIsco 3750
Does that make sense?  Or can you set the first Linksys to do NAT (or is it out of your realm of control?)
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by:Paktusjet
ID: 22656146
the main linksys is natting but heres how the setup kinda looks..

computer -----> 3750 -----> linksys -----------> modem
                                                    (NAT)

I have one class C given to me. which is 192.168.1.0. I'm running out of room on that C network. So I need to implement 2.0 and 3.0. My Linksys doesnt know about the 2.0 and 3.0 network which Is why I need it to mask them 2 networks. And yes there is a reason behind all of this, but it is fully supported :) I just can't change the linksys.
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by:sstone55423
ID: 22656197
Change the NAT'ing Linksys to NAT the 192.168.0.0 255.255.0.0    That is, change to use a class B (/16) network instead of a Class C (/24).  Then you get lots more IP addresses, and can still route between them without changing anything on the PC's.
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by:sstone55423
ID: 22656201
Well, if you truely can't change the existing linksys.  Like I said, get another Linksys.  Make it's outside address 192.168.1.x and then set the inside addresses to 10.1.0.0/24 and you will have plenty of inside addreses.
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by:sstone55423
ID: 22656202
Whoops  10.0.0.0/8 ot 10.0.0.0/16  (not 24) or you will be no better off.  I better get some sleep.
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by:Paktusjet
ID: 31503686
I just wish there was another way :)
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