NAT translations DHCP and acess to internal servers

aducey01 · ‎01-20-2013

I'm using a 2601X router connecting to a broadband connections. The following NAT connections is working but I need to do NAT exemptions to set up my VPN appliance on the DMZ. I see a lot of documentation on how to use a pool of public addresses to do that, but I only have the one dhcp address from my isp. Is there a way to make this happen?

!

boot system flash:c2600-adventerprisek9-mz.124-25d.bin

!

interface FastEthernet0/0

ip address dhcp

ip nat outside

ip virtual-reassembly

duplex auto

speed auto

no clns route-cache

interface FastEthernet1/0

description DMZ Subnet

no switchport

ip address 10.33.33.1 255.255.255.0

ip nat inside

ip virtual-reassembly

!

interface Vlan22

ip address 10.22.22.1 255.255.255.0

ip nat inside

ip virtual-reassembly

no clns route-cache

ip route 0.0.0.0 0.0.0.0 dhcp

!

ip nat inside source list 1 interface FastEthernet0/0 overload

access-list 1 permit 10.22.22.0 0.0.0.255 log

access-list 1 permit 10.33.33.0 0.0.0.255 log

cadet alain · ‎01-20-2013

Hi,

just replace your standard ACL for NAT by an extended one where you deny traffic from this DMZ to the distant subnet for which you are using the VPN.

Regards.

Alain

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aducey01 · ‎01-20-2013

the acl is for NAT, not VPN...does that make a difference?

I'm thinking I need static mappings for the dmz ip's that I want exposed to the internet...

cadet alain · ‎01-20-2013

Hi,

yes if you want to do port forwarding then you need a static PAT entry like this : ip nat inside source static tcp 80 x.x.x.x interface x/x 80 ( this example is for web service on the internal host).

But you were talking about a VPN so if this server communicates with another subnet through a IPSec VPN then you'll need to do NAT exemption.

Regards.

Alain

Don't forget to rate helpful posts.

aducey01 · ‎01-20-2013

Thanks so much, can you show me what a nat exemption would look like or is the example you gave me a nat exemption? how is it coded?

thanks

aducey01 · ‎01-20-2013

ok to ssh to my router from the outside, I used the following:

ip nat inside source static tcp 22 10.33.33.1 interface vlan 33 22..

Is that what it's supposed to look like? It's not working.