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I have a Windows XP machine that is fitted with two Network cards. One card is used to access the company network and internet and its IP is assigned by DHCP whilst the second has a fixed IP and is used to program a specific type of hardware (let me refer to is as a 'converter' from this point onwards) via a cross-over Ethernet connection in a production type environment.

The first step in programming a converter is for it to be discovered by the XP machine and this is achieved using a multicast on address causing ANY converter connected to the Ethernet cross-over cable (adpater 2) AND converters connected to the company network via adapter 1 to respond with their MAC address and hence be 'seen'. This process is currently done through a piece of software provided by the manufacturer of the Converters.

I want to be able to restrict this multicast to the adapter with the FIXED IP and hence thought I could achieve this by adding a route to the route table. I then thought that any multicast to would be directed to the second adapter only and hence only the converter to be programmed would be 'seen'. Unfortunately this is not the case and even after adding the route to the routing table those Converters on the Wide Area network continue to respond to the multi-cast.

I notice in the Ip tables there is the address entries for BOTH adapters i.e. anything on is directed to both of them however I want, in the instance of to be directed to the second adapter only. I have tried to removed from the tables but windows will not let me do this reporting 'cannot find route'

Can I achieve the above? How can I make my IP entry a priority over the entry?

Any help is appreciated.

share|improve this question
Software doesn't have the ability for you to choose an interface? – Tim Jan 10 '12 at 17:58
No it dosn't and I think it's an O.S. determined thing. I think even at application programming level it's difficult to select which adapter to use. (This is an ultimate aim by the way to automate it with a Java program). It appears easier to try and alter the IP tables if possible. – Kerubu Jan 10 '12 at 18:19

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