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HELP: How do i pass through public IP's from dialer interface to physical interface without NAT?

Matthew burnley
Level 1
Level 1

 

 

Hello,

 

I'm having alot of trouble trying to do something reasonably straight forward, or so i thought.  I have been given a /29 ip block by my ISP, im using a Cisco 2811 router with an ADSL HWIC.  If i set the dialer interface to "ip address negotiated" it works fine, but i want to put that ip block directly on the inside interface so i don't have to use NAT overload or static 121 NAT.

 

I have tried putting my block of IPs on Gi0/1 and removing "ip address negotiated" from the dialer interface and replacing it with "ip unnumbered GI0/1" thinking it would force the dialer interface to take the ip from the GI0/1 instead.  However i just cant get out to the internet when i do this.

 

Am i missing any commands or am i doing it wrong?  I have googled this o nthe web but can't seem to find the answer which is odd, everybody uses NAT instead.

 

Passing through a public block from an ISP to a physical interface shouldn't be too difficult surely?

 

 

Can anyone crack this for me?

 

 

Many thanks!

 

Matthew

 

Just as an extra note i found this article which is similar to what i want to do but uses a vlan interface (because its a 887 and has switchports for access)

http://forums.thinkbroadband.com/fibre/4133359-cisco-887va.html

 

 

2 Replies 2

Matthew burnley
Level 1
Level 1

Ok i have cracked it, i had a typo in the IP address on the physical interface, this now works as intended, it appears i have answered by own question.....

 

 

Cheers anyway.

 

Matt

Hi Matt,

Could you post a config of yours.

I am trying to do a similar thing. I've got a block of /29 addresses, and would like to use 1 Public IP for the router and 1 Public IP for the firewall which is behind the router.

Did you have to Bridge the Dialer interface with FA? 

How did you end up solving this mystery?

I also do want to avoid 121 NATing.

Thanks!

Dawid

Review Cisco Networking products for a $25 gift card