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MS Proxy 20 and IP Forwarding

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by ezpcc 1 view

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This is my first attempt at implementing MS Proxy and have a problem. Have a stand alone server with NT 40 Sp6a and MS Proxy 20 SP1, 2 nics and 3com switch. Using laptop with Win98 as test client on internal network. Installed Proxy with external address of 192.168.1.15 and internel address of 192.168.2.15. The external nic is connected to a hub, then a router that is doing NAT to an ISDN link. The ISP has configured the NAT relations correctly. Disbled access control and packet filering on theProxy server and setup the LAT with the internal address of 192.168.2.0 - 192.168.2.255. The test client can access the internet for HTTP, FTP and Mail fine. Here is were I get into trouble. The domain PDC in on the side connected to the external NIC on the Proxy server. When I try to log into the domain from the test client, no domain server is avaiable. When I try to ping an internet address, the name is resolved to an IP address but receive error message, destination host unreachable. The same is true with internal addresses. I entered a host file and have WINS server running. Addresses from both networks are being registered to the WINS and I can resolve host names via the host file but the ping and tracert commands fail. So, I turned on IP Forwarding thinking the packet is not getting routed accross the 2 nic cards and still have the problem. Can anyone tell me what I am missing here?? Is the fact that I am running Proxy 20 causing the ip forward featuer of NT to not work?? I want to implement VPN at a later date and from what I have read here, this issue may come up again then. Thanks in advance for your help.

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by mckaytech

You've implemented kind of a different system and have effectively double-NATted your addressing system. Since you already have a NAT router, I'm curious as to what you hope to accomplish with your Proxy Server.

Normally, your PDC would be part of your internal network inside the Proxy Server. With it located where it is, I can foresee all sorts of problems cropping up both with routing and name resolution.

IP Forwarding and Proxy are not used together because that would defeat the purpose of the Proxy Server. IP Forwarding just routes packets from one interface to another and therefore would bypass all the Proxy Server protections.

I hope you take this in the spirit in which it is offered, but I think you need to re-consider your architecture and consider having all parts of your domain inside the Proxy Server (if, in fact, you even need Proxy Server at all). I don't see any way to get the current setup to work properly. although I would be glad to be proven wrong.

paul

by ezpcc

I have done more research and acquired the book on Implementing and supporting MS Proxy... the original idea was that there is an IIS server currently being accessed with an external address and I did not want to move that server into the internal network. As I dug deeper I come to the same conclusion as Paul and will now be useing the Reverse Proxying and Hosting feature of MS Proxy to accomplish what I need. Thanks again for your help.

by dc1

Pwrights answer is absoulutely correct. When setting up a Proxy that machine is usually either you gateway to the internet or is connected to a router as you have it currently configured. You are essentially double NATing your internal network with your current configuration.

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