Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Multiple Subnets/IP Addresses on single Router Ethernet Port (no vlans)

I would like to know if there is a way to setup two separate IP addresses on a single Router Ethernet interface. Basically what I am looking at doing is providing a client an ethernet dropout from a router that has a private 192.168.x.x subnet and doing port address translation outbound on those addresses, but this client also needs a small 30 host subnet of registered address, but does not want to handle any of the routing or translation of those addresses.

Is it possible to setup both a private and a registered ip address to one ethernet interface without having to use vlans or setup translations on the router?

The current ethernet interface is configured as follows:

interface FastEthernet0/0

ip address 192.168.1.1 255.255.255.0

no ip proxy-arp

ip accounting output-packets

ip nat inside

no ip mroute-cache

speed 100

full-duplex

no cdp enable

5 REPLIES
Silver

Re: Multiple Subnets/IP Addresses on single Router Ethernet Port

ip address n.n.n.n m.m.m.m secondary

New Member

Re: Multiple Subnets/IP Addresses on single Router Ethernet Port

You should probably match your NAT with a ACL, so that you only do NAT on the prefered subnet/addresses.

New Member

Re: Multiple Subnets/IP Addresses on single Router Ethernet Port

Would IP address a.b.c.d 255.x.x.x secondary help?

New Member

Re: Multiple Subnets/IP Addresses on single Router Ethernet Port

I am actually trying the ip secondary, but I cannot seem to route inbound beyond the interface secondary address. Any hosts connected after the initial secondary address timeout on an inbound connection. outbound seems to work fine though, Any other thoughts?

Cisco Employee

Re: Multiple Subnets/IP Addresses on single Router Ethernet Port

Make sure you include the secondary IP address under your routing protocol configuration using the appropriate network statement.

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
845
Views
0
Helpful
5
Replies
CreatePlease login to create content