Multiple IP assigned to one NIC problem

Have a Win2k server setup with ISA Server acting as a firewall. Behind it I have 2 FTP sites running on 2 seperate machines with the external addresses on the firewall forwarding FTP requests to those sites. The problem is that when Someone makes a request for FTP site B the response from the server goes out with the IP of Site A so any firewall at the client side is blocking the responses since there are no clients trying to establish a connection with that IP address. Is there anyway of having it set to send back responses with the appropriate IP address on the data?

Now THAT'S an interesting problem. If I find anything out I will let you know. Have you run that by Microsoft??

*Knows this is above his head but would be very interested in hearing what the pros say.*

-Danyll
:D

this might be stupid question but..

Do you have both ftp servers on different ports and are you forwarding the correct ports to the correct machines (IP Addresses)?

James

I am working on it right now...

I have a friend who wrote the ISA book, and she is looking into it too...

I may need to set this up in my lab to figure it out, but it would be worth it, so hang tight...

Shadowking

[quote] I may need to set this up in my lab to figure it out, but it would be worth it, so hang tight... <hr></blockquote>

Who the f are you? Batman???? :eek:

lol

[quote]Originally posted by confus-ed:
<strong>Shadowking,

Who the f are you? Batman???? :eek: </strong><hr></blockquote>

I am MUCH more diabolical than Batman. :)

Naw. I am a writer, but I have a lab that I control for a group of writers so that we can set up network scenarios and document them. Right now is a down time for that lab, so when I have some free time, I will see what I can do.

OK, been doing some thinking.

Try to unplug or disable that interface and see if you can connect at all.

It sounds like you cannot send packets from the second interface.

I will have to wait until next week to set this up, but I will take a look at it.

bump.

I wanna see shadowkings answer in full, when he's finnished righting the worlds wrongs.....

Shadowking get out of my lab and tell them.

Wot? No Superhero...

Sorry all,

Maybe I forgot to check the e-mail notification.

czone - Not a stupid question, I always try to start with the basics and it would be a question I would ask someone else. The FTP sites are both on port 21. I know I can do different ports but I think my problem will still continue of assigning the wrong IP on the rebound. I am using the server publishing rules to decide who goes where by the IP address they come in on.

iamtheman - Have not run this by Microsoft, doesn't that cost money?

DSTech - you just get to read about it, I had to figure it out :D

confus-ed - thanks for bumping it because I probably would of not seen my own topic even though I check this forum like a 100 times a day.

ShadowKing - which interface are you referring to. I have three NICs on the server. One for LAN, One hooked up to the cable modem with the 2 external IPs, and a third hooked to DSL that the ISA Server rolls over to as a backup if the cable modem should go down so the internal network can keep browsing the web. Are you speaking of Schinder?

Again, sorry I have been missing my own topic, thanks for al of the replies, I hope to keep tabs on this now. We have gone down to one FTP site but I would like to go back to the old way to seperate the sites. Plus, whats the point of paying for 5 IP's if your firewall can't use them correctly.

Tony

OK, guys, sorry I have not gotten to this one...

Things have been busy this week when they were supposed to be dead...

I am aware and working on it. I wanna find this one out myself...

Sooooo... I really do have to do my work at work, but when that work is done, then I can do my fun stuff...

Just get an AGP one, it'll go faster as well.

Yes, I know. :)

so.. you are able to use port 21 on 2 different servers? Cause some routers can only have a single port going to certain machine..

[quote]Originally posted by czone:
<strong>so.. you are able to use port 21 on 2 different servers? Cause some routers can only have a single port going to certain machine..</strong><hr></blockquote>

If I understand the problem correctly, He has 2 NICs in the computer, which gives him 2 IP Addresses. The Win2k box IS his router. When a client connects to IP A on port 21 it works fine. However when client connects to IP B the server responds from IP A, which makes the client's firewall unhappy.

[quote]Originally posted by ShadowKing:
<strong>

If I understand the problem correctly, He has 2 NICs in the computer, which gives him 2 IP Addresses. The Win2k box IS his router. When a client connects to IP A on port 21 it works fine. However when client connects to IP B the server responds from IP A, which makes the client's firewall unhappy.</strong><hr></blockquote>

Bingo, thats how its working. czone, I am running Microsoft's ISA Server on a Win2k Server computer which allows that computer to act as my network's firewall/router.

Here's the NIC breakout:

External NIC 1:
X.X.X.A
X.X.X.B
Hooked to our Primary connection which is a Cisco Cable Router

External NIC 2:
Failover connection to a DSL Line

Internal NIC:
This one is hooked up to the network

The Cisco cable router is not doing anything accept forwarding packets onto my firewall. I am wondering if this problem would be solved by installing another NIC in the server but I already have 3 in it. Seriously thinking of setting up a second firewall using Linux but I am not very Linux strong so it would probably be more of a security risk.

ok i get it.. sorry for the confusion..

for some reason i keep thinking dns, but i doubt it.