Strange Problem with Load Balanced FTP

[rpreston]

I have two servers running W2KAdv, with IIS5.0.

These servers are running under network load balancing, sharing ip address X to provide fault tolerance. The two servers, A and B, have local ip addresses Y and Z, respectively.

I need to make a change to the FTP configuration, so I've taken server B out of load balancing leaving the remaining server A to deal with live transactions. However, I'm now seeing something I don't understand.

If I now try to FTP to the local IP address Z of server B, it doesn't work. Using DOS FTP I get the message :

User cannot log in, home directory inaccessible.

So, I tried the same on the local IP address Y on server A to make sure that was still OK, but I get the same problem.

However, if I FTP to server A using exactly the same username and password, but to the load-balanced IP address X, that works.

So, my security/permissions work when using FTP to the load-balanced IP address, but fail when using FTP to either of the local IP addresses.

I'm a bit stumped here. I'd be extremely grateful if anyone can spot the problem.

TIA.


Rob