How to get IP address

[michael_green]

Hi All,

Does anyone know of a neat way to get the IP address of a machine from within a Fortran program? I can spawn a console program to run ipconfig, etc, but that's seems clumsy - I'm surprised there doesn't seem to be a Windows API function for this. Have I missed something?

Many thanks in advance,
Mike

[Steven_L_Intel1]

This MSDN article shows how to do it from VB using the Winsock API. You can probably figure out how to do this in Fortran from the example here.

I note that the gethostbyname function has been superseded by getaddrinfo from WS2_32.lib, but I also note that Intel Fortran doesn't provide an interface to that in module WS2. gethostbyname is in module WSOCK32.

[michael_green]

Many thanks, Steve,

The MSDN article demonstrates how to get all the IP addresses used by the machine "if the machine is multi-homed" (to quote from the article). I have already retrieved that information from reading the registry, but none of it helps me because I need to know the IP address in use at the time the program is being run. If I can get that, I can use it to determine which of many servers to connect to. The logonserver environment variable looked good for a while, but it has proved totally unreliable and is a big disappointment.

Thanks again - and season's greetings from down under,
Mike

[IanH]

Remember that machines don't have IP addresses - adapters do. There may be multiple IP addresses "in use" at any time, trivially 127.0.0.1 etc, but consider VPN's, multiple network cards, VPN's, IP4/IP6...

What are you trying to do?

If something isn't available in Winsock then there's a lower level IP helper library that gives you equivalent information to ipconfig. I've used it in the past from C to get MAC addresses for ethernet adapters.

[Paul_Curtis]

See attached code module and library, which discovers the IP addresses of all active adapters, as well as the current network gateway IP and the MAC address of the computer.

[michael_green]

Thanks Guys, that's exactly what I needed.

To answer the question "what am I trying to do?" - there are dozens of servers in my environment spread over an enormous geographical area. Software I develop needs to know where it is being run from in order to connect to the appropriate server. From a list I have been given by our systems people I can work out where the user is located by using the subnet IP address. This system works well when I capture the output from ipconfig and get the information from there, but I hate to see a console window flashing up each time anyone starts a program.

Many thanks again.

Mike