FTP with 2 network cards problems.

[DougFerguson]

That is already the case. That was dictated by MAX searching for new targets only on the primary NIC.

Its strange because it establishes communciation on the correct NIC. This only a problem when Windows asks the target (after connection on port 21) to change the data port. For some reason Windows is asking for that data port to be on NIC2.

[DougFerguson]

Here is a Wireshark capture. The failed connections are followed by a successful connection after I disabled NIC2 and cleared the ARP cache.

[DougFerguson]

Here is my routing table...

The IP address of my private network is 10.100.0.1.

The IP address of the other network card, which we will use for internet connection is 10.30.40.103.

How do I edit this route table to ensure that all FTP communication from IP addresses 10.100.0.2 through 10.100.0.10 goes only to NIC 10.100.0.1?

Would it be something like this?

route -p ADD 10.100.0.2 MASK 255.255.255.240 10.100.0.1

[DougFerguson]

OK, I was looking at the capture table wrong. It appears that it is LabVIEW that is reassigning the wrong network card when asking for a DATA port. Specifically its in the FTP Open Data Connection.vi. If the Active input is TRUE its uses the TCP Create Arbitrary Listener.vi, which in turn calls the TCP Create Listener Function but does not wire out a control for the net address. For some reason LabVIEW finds the listener on the 2nd NIC. So as the KB on page one of this thread suggests I can change the Active to FALSE and see if that works. Otherwise I'll pull that control high enough to wire in the net address I want it to use.