Avatar of smartit_richard
smartit_richardFlag for United Kingdom of Great Britain and Northern Ireland

asked on 

Can a Cisco 877 Router be configured for BT UK Multi IP address?

I am looking at a solution for a client who currently uses a BT 2 wire router with a single ip address, there is another customer in the building now expanding and wanting to use their own mail server.

When i configure a BT 2 wire for multi ip address you have to do this via address allocation and this makes the router transparent, i would like to know if the cisco can hadle 5 ip addresses from BT and if i can use basic routing as:

ip nat inside source static tcp <local> 25 <public ip> 25 route-map SDM_RMAP_1 extendable

You may ask why i dont just use the BT box, but the client does some work for the other tenent in the building so i will have to configure vlans with access between them.

Any advice before i commit to a solution would be great.
RoutersCisco

Avatar of undefined
Last Comment
smartit_richard
Avatar of Istvan Kalmar
Istvan Kalmar
Flag of Hungary image

HI,

it isn't working you must config only ona address to translate:


ip nat inside source static tcp <local> 25 <public ip> 25  extendable
ip nat inside source static tcp <lacal2> 25 <public ip_2> 25  extendable
Avatar of smartit_richard

ASKER

This was my plan, but BT in the UK is very odd with IP address allocation, do you think this will work?

i guess i must allow the router to negotiate the initial WAN ip then setup NAT as:

ip nat inside source static tcp <local> 25 <public ip> 25  extendable
ip nat inside source static tcp <lacal2> 25 <public ip_2> 25  extendable

has this been tested with BT?
ASKER CERTIFIED SOLUTION
Avatar of Istvan Kalmar
Istvan Kalmar
Flag of Hungary image

Blurred text
THIS SOLUTION IS ONLY AVAILABLE TO MEMBERS.
View this solution by signing up for a free trial.
Members can start a 7-Day free trial and enjoy unlimited access to the platform.
See Pricing Options
Start Free Trial
Avatar of smartit_richard

ASKER

I am happy with the solution and will recommend this to my customer. if anyone feels this will not work please advise.
Avatar of PSLmike
PSLmike
Flag of United Kingdom of Great Britain and Northern Ireland image

BT in the UK do allocate WAN IP addresses very strangely....

If you have multiple static IP addresses, then they allocate the "outside" router address dynamically and then route your multiple IP addresses to that dynamic one - confusing, eh?

Typically, I would allocate on of the subnet to the router (add as a loopback on the cisco), so the router can be managed from my network management centre on the outside. The other statically allocated addresses can be simply added to the nat statement similar to your original post. The router knows how to deal with these for you. What do you have in the route map? You may not need it to be that complicated...
Avatar of smartit_richard

ASKER

I completly understand what you are saying in your post so i just use the NAT statements to inform of traffic, good news i guess, router management from the outside is a no no for me anyway as we would only ever manage from inside.

As for the route map this is all sorted i just has to get my head around BT and its odd manors..

Thank you for your help.
Routers
Routers

A router is a networking device that forwards data packets between computer networks. Routers perform the "traffic directing" functions on the Internet. The most familiar type of routers are home and small office cable or DSL routers that simply pass data, such as web pages, email, IM, and videos between computers and the Internet. More sophisticated routers, such as enterprise routers, connect large business or ISP networks up to the powerful core routers that forward data at high speed along the optical fiber lines of the Internet backbone. Though routers are typically dedicated hardware devices, use of software-based routers has grown increasingly common.

49K
Questions
--
Followers
--
Top Experts
Get a personalized solution from industry experts
Ask the experts
Read over 600 more reviews

TRUSTED BY

IBM logoIntel logoMicrosoft logoUbisoft logoSAP logo
Qualcomm logoCitrix Systems logoWorkday logoErnst & Young logo
High performer badgeUsers love us badge
LinkedIn logoFacebook logoX logoInstagram logoTikTok logoYouTube logo