How can I have 2 I/P address linked to one NIC ? 1

[cyberdyne]

Hi folks !

I am facing a problem ( Not actually) with IP address.

To tell you my requirment in brief I have a network in my office and that is simple peer to peer n/w through MS TCP/IP protocol.

I also have a local internet service provider who is giving internet connections to individuals through proxy. For this I have to assign an IP address to his computer ( Server). and this ip address is different from whati am using in my office. also i hv to specify Gateway, DNS.

Now if I want to connect to internet i hv to change IP and other settings. and if i want to connect to office n/w i again hv to change IP address.Also there is a security question as If I share my harddisk for office people it
can be viewed by the people on internet n/w. so i hv to stop sharing also when i connect to internet.

This is very tiering job. I want a solution for this.
Is this can be solved by putting 2 NIC in the system ?
Will this provide security against ppl as i hv describe earlier?

Pls help .

 

[sobak]

What OS are you running? I know for a fact you can do it with 2000 or Windows NT, not sure about 9x or ME. Let me know if you're on an NT platform and I'll tell you how.

david e

 

[Zelandakh]

How do you get to the Internet? Modem, cable, DSL, leased line?

What is your OS?

 

[cyberdyne]

hi ! my OS is win98se.

I also hv a pc with NT 4.0 sp 6a. But i dont wanna access internet from that machine as there might be virus attack on that PC and that is very crucial machine. So no net access on that PC. Can i do that with 2 NIC in my PC with 98se OS ?

 

[Zelandakh]

I don't think 98 supports multiple NICs. You come you have NIC link to the Net?

 

[sobak]

What you will need to do is install two nics into the Windows 98 system. The Windows 98 OS does not support two IP Addresses to one network card as Windows NT does. I believe once you install the second nic, the connection to the internet should be seamless, of course I haven't supported Windows 98 for a long time so I may be wrong. Try it and let us know if it works out for you.

david e

 

[cyberdyne]

Friends thank you very much for your valued reply!

Well I dont mind putting second NIC in my computer but i wonder about the security.

will any one on internet network be able to see my shared drives (which i hv for my office network only )and sneak in if i hv two NIC in my system? The IP addresses configured to both NIC will be different. so how can i know that drive being shared is for one perticular IP address.

 

[sobak]

You are correct to worry about security! Only next option is to install a proxy server or a router, without knowing specifically how your network is set up both should perform the same function. Of course both will require additional equipment, the proxy server will require a system with two network cards installed, one set to your Internet Connection and the other to your LAN. The router will also perform the same function, of course it depends on how much you would like to spend. Since I only deal with Cisco Routers I can only speak about those but I am sure there are some others out there for a much cheaper price than Cisco. Then you have the proxy server option, this would require a system running any windows product (9x, NT or 2000) most companies make software that will run on all platforms. I know one I've used in the past has been WinProxy, it is pretty good and has a lot of options you can set for security. Both of these solutions will isolate you and your Internet but they have to be configured right, a mis-configured piece of equipment may leave you wide open to the internet.

david e

 

[Zorlod]

Any time that you connect to your isp, there is a security issue, not only can they see things on your computer, but also, with enough time and maybe a bit of luck, they could possibly dig around on any other machines hooked to your network. Depending on the nature of your information throughout the network, you may want to look into getting some sort of firewall, whether it be hardware or software. To find more out about internet security check out

http://www.grc.com

, its a pretty good site with some cool utilities. You'd be amazed what hackers can do in a matter of seconds.

 

[BIS]

Just a quick note. If you are looking for a cheap router/proxy and you have an old 486 lying around, why not try out something like FreeSCO (

http://www.freesco.org).

 

[cyberdyne]

Well friends I wil definately try it out.

Thanks ZORLOD for a very 8useful site recommandation.

Sobak Thanks a lot for yr help and suggestions.
I will try out a proxy option first. I will be using wingate. Tell me one thing again if I use two lan cards each with different IP address, One for internet and other for my office network are there any chances that shared resources on my network can be available to the people on internet network ? (My Internet network is also a proxy where people are connected through cat5 cable around our area. I was able to go into some peoples hard disks if they had kept shared without password. Though I did not do n e dammage as it is against morality! but i dont want same thing to happen with me.

tahnks again

Apoorva

 

[sobak]

You would need to close all ports but a select few....of course the fewer ports closed the better. Also keep in mind that if you're not running a web server Port 80 inbound can be closed but needs to be open outbound to allow your office to browse the internet. The following are common port numbers that are open, you know the best as to what you need open and what can be shut down.

25 smtp
80 http
113 pop3
443 shttp <---I'm not sure about this one

I believe Windows shares go over port 137 locking down the ports both incoming and outgoing will protect you somewhat. Once you get the software installed and get everything up and running you can check your security at

http://www.dslreports.com/secureme

. This will give you a basic scan of your proxy server and report back to you what it finds. For an intensive scan you can purchase some points that will allow you more ports to be scanned. Keep in mind that the proxy server will be the point of entry, the only function of this box should be your connection to the internet.

Security is always the forefront of my mind, and should be for all network administrators. Keep a log running on your proxy server. It helps in two areas...

1. Assist you in troubleshooting.
2. Monitor your network for possible hacking attempts.

don't be surprised if you see many people scanning your network. I average about 150 different IP addresses a day scanning my network.

Hope this helps, let us know if you have any further questions. :-> david e

there are just some end-users that need reBOOTing!!!!!