Thread: How to assign Public Static IP to either a PC or the WAN port of wireless router

Hi everyone,
I'm a MTNL Mumbai subscriber on the 1599 Unlimited plan. I'm currently connecting the mtnl adsl modem to a linksys wrh54g wireless router on the LAN port with the WAN port on the Linksys disabled so as to share the internet with the machines and PS3 in my home.
Recently I applied for a static IP from MTNL and have received the same. Now here's the question:
Is it possible to have the Public IP received from MTNL assigned to either the WAN port of my Linksys router or to any of the other machines. I have tried literally fiddling with the Bridge mode setting on the ADSL modem but wasnt really succesfull.
My MTNL ADSL modem is T-KD 318 EUI.
My setup is:
Static IP --> ADSL Modem
LAN IP from ADSL --> Linksys LAN Port (192.168.1.x)
Desktop connected to Linksys LAN Port (192.168.1.x)
DHCP Enabled on ADSL Modem. Disabled on Linksys.
Laptop and PS3 connecting to Linksys via wireless using WEP and MAC address binding.

literally fiddling with the Bridge mode

Previous thread:
There are multiple ways of setting this up.......
http://www.indiabroadband.net/mtnl-b...tml#post257191 (Wireless Configuration With UT300RU and Linksys WRH54G)
You are using linksys as a switch. All worked smoothly including wifi mode
as per this thread.
1.
Uncheck"bridged" and select PPP/PPPoE
2.
In wan page enter your userId and password. etc.
Check in "Broadband How to" guides by @Just4kix.
Procedure same for any adsl modem +wifi router combination.
3.
Adsl modem T-KD 318 EUI is same as ut300r2u (bsnl new model 0r WA3002-g4 Less wireless settings )
4.
Connect rj45 from adsl modem as usual to WAN port of Linksys wifi router.

Is it possible to have the Public IP received from MTNL assigned to either the WAN port of my Linksys router or to any of the other machines. I have tried literally fiddling with the Bridge mode setting on the ADSL modem but wasnt really succesfull.

Possibly, but I don't see what good it would do you and I don't think this is the way to go

Static IP --> ADSL Modem
LAN IP from ADSL --> Linksys LAN Port (192.168.1.x)
Desktop connected to Linksys LAN Port (192.168.1.x)
DHCP Enabled on ADSL Modem. Disabled on Linksys.
Laptop and PS3 connecting to Linksys via wireless using WEP and MAC address binding.

Fine. Forget that your Linksys is a router (you are not using the WAN port, so it isn't actually routing) and think of it as a hub/switch.

The router on your network is the ADSL modem. Typically it will have LAN IP address 192.168.1.1. It should be in router mode, not bridge. Also known as "always on" it should be logging you into the ADSL net. There should be no "dialup" from any pc on your LAN.

That shoudl all work. So, next... why did you go for a fixed IP? Are you wanting to run webserver etc? If so, then: on the machine that you are using as a server, assign a fixed (not "obtain an IP address automatically) 192.168.1.n address. Either turn off DHCP on the ADSL modem, or configure it to use a pool of addresses other than any fixed address you use.

Then... Check out your modem config for virtual servers, port forwarding, NAT, etc, and search this forum for info, because this is far as my memory takes me

Thanks for the reply..

essbebe -
My ADSL modem is currently running in PPOE mode only.. not bridge and has NAT enabled.

The link you posted is to my own post which has a working configuration like it is right now and even the link from just4kix gives a solution which I have already tried. It still assigns LAN IP to the Linksys WAN port. I got a fixed IP or security purposes (IP Camera).
Also, my PS3 shows the NAT as Type 3 which is heavily restricted in terms of game hosting/voice n video chat on PSN. If I'm able to work out a solution where the fix ip can be assigned to PS3 (although temporarily) that would resolve a lot of my other problems.

So you see... the need for this Fixed Public IP and being able to assign it to a particular machine is multi faceted..

I have also tried setting the Linksys in PPOE mode and supplying the username and password info and the ADSL modem in Bridge mode connected to WAN port of Linksys. But that didnt work either. Even though the ADSL modem status still showed as connected, IP was not assigned to the router and internet was not accessible.

So I guess I'll need a

First, understand that your router is on MTNL's network, and it must have an ip address. Whilst that IP address is, for DSL subscribers, normally dynamic, you have bought a fixed one. This does not mean that you can do what you like with it, or assign it to any device: it is good for one thing only, and that is being assigned to a device on the network to which it belongs. You cannot assign it to a device on your LAN.

Let's make up a number and pretend it is your fixed MTNL IP: 59.125.63.7. How could you assign that address to a device on a 192.168.1.0 network? You can't.

(You can configure your modem in bridge mode, a you know, attach one PC to it, and have that PC be 59.125.63.7 --- because that one pc now becomes a device on MTNL's network, not any any local LAN of yours. For security reasons, this is very,very much not recommended)

So what can you do?

1. This is what I have experience of, but it was with leased fibre lines costing UK-pound equivalent of Rs70,000-plus a month, and had the service to match... buy not one, but a small block of IP addresses. IIRC we had four or eight. I cannot remember how this was done, and didn't speak "cisco" anyway, but our router would receive packets for any host in that block. We had a mail server: we assigned one external address to that mail server. That is what you would get from DNS if yur mail server was looking for ours. However, our mailserver was on our internal, private-net-space, 192.168.1.0 network. Simple: NAT on the router just did a straightforward conversion of external/internal addresses.

2. You have only got one IP: is it still possible? Yes. But you must do it by virtual server/port-forwarding. Say you have a web server on 192.168.1.100. If I enter your www . Domain . Name in my browser, my machine gets told that's 59.125.63.7 by DNS. When my web packets arrive at your router, it says, html? That'll be for 192.168.1.100. If we are talking some other service or protocol, then you have to find out the ports to forward.

That's how it is done. The first thing to recognise is what you can't do.

Originally Posted by Nick_H

(You can configure your modem in bridge mode, a you know, attach one PC to it, and have that PC be 59.125.63.7 --- because that one pc now becomes a device on MTNL's network, not any any local LAN of yours. For security reasons, this is very,very much not recommended)

Thanks Nick!! I understand that the above undesirable, but that is what I want to do. The problem is that I even tried setting up the modem in bridge mode and tried connecting it directly to my PC and not the linksys router. It still would not dial using the ISP's username and password supplied. I can work my way up if you can help me get this working on my PC.
I had configured this about 4 years back on a NITIX box in my office so it could be exposed to the net in order to host the mail and file server. In that case the Fixed IP alloted was assigned to the ETH 1 interface of the server itself and not the modem. So I know this is possible but I am unable to get it working in my scenario.

Lets cut this short. Can you help me set this connection in bridge mode if I only wanted to connect my PC and have the Fixed IP assigned to it instead of the modem?

Lets cut this short. Can you help me set this connection in bridge mode if I only wanted to connect my PC and have the Fixed IP assigned to it instead of the modem?

A straight answer to a straight question --- No.

--- as you can see, my professional experience was different (and seven years ago now).

--- I had a fixed IP on my home ADSL back in London. I used it for VPN stuff, but never ran any server at home or had any incoming traffic.

--- Here it's been dynamic IPs all the way for five years anyway, with no need for anything else, and I did not use bridged mode for more than an hour after the installation engineer left

This is probably a really, really really dumb question but no help available from MTNL? Of the two companies I've dealt with here, Airtel engineers do seem to have some technical knowledge, but the BSNL guys know --- how to twist wires together!

Sorry not to be more help.

Thanks buddy. I like straight replies. So no issues.
As far as help from ISP is concerned, here's an abridged transcript of the conversation I Had(I had the conversation in Hindi, so I'm just translating it):

================================================== =====
Me - Hi, I received a Fixed IP from MTNL this evening and since then the net is not working. Can you give me the configuration details for the same?

MTNL - 1 minute. Where's the book?(manages to find some book and then..) Goto 192.168.1.1 and enter username and password as admin/admin. Then go to Status page and there does it show your Static IP that is assigned?

Me - Yes. it says connected and shows the IP(Note that I havent set the modem to operate in static IP mode). But I'm not able to access the net.

MTNL - (Regardless of what I said, continues reading from the Online Help Guide which I have already gone through about 20 times by then) There IP address will show 59.x.x.x and subnet mask show... blah blah .. and the gateway shows blah blah..(she said the same IP as the one mentioned before).

Me - But, my IP address is 120.x.x.x and gateway is 59.x.x.x and my net is not working even though it shows status as connected.

MTNL - (Looong silence.. finally leading to disconnection)
=================================================

So I guess I'm on my own or may be I'll try calling a couple more times and might get to someone who knows this.. but thats hoping for too much..

Oh yes, they know how to read scripts too... except the BSNL script used to say "someone will call you in 24 hours". If pressed, they actually had information about stuff like network status, "Oh yes: your area is down, it will be two hours".

Good luck with your config