NetBurner Community Forum

Hey Guys,
I'm using SB70LC, now its running a Modbus Application. The Modbus Server/Slave works great but now i'm having an issue when i'm trying to connect to another controller. I execute the 'connect' and it times out, i see activity but for some reason i can connect. Is theirs anything i'm doing wrong? This is a TCP to TCP app.

Code within a Class object: The controller is on a DHCP network.
const char *pIP = "xx.yy.zz.aa";

IPADDR addr = AsciiToIp(pIP);
m_handle = connect(addr,0,502,TICKS_PER_SECOND*10);
Operation times out and m_handle is always -1.

Please let me know if i'm missing something.

Ed

Probably need a little more info here. But you can try a couple of things, just to exonerate the NetBurner client. Assuming you have a PC on the LAN with your NB. Can you ping the controller? If so, can you open a DOS prompt and Telnet in using port 502?

If you can do that then you know nothing between you and the controller is blocking that port (like a firewall), and noone else is already using that port. So make sure you ctrl-] and quit Telnet before going on.

Please excuse my potential ignorance but I don't know anything about ModBus and I'm assuming it's somewhat irrelevant to your question as you're just trying to connect over TCP/IP from a client to a server.

I'm assuming that you don't have "xx.yy.zz.aa" in your ip string but some actual valid address you didn't want to disclose (or maybe there's a magic address I don't know about?) Other than that your use of connect() looks fine.

Is the controller on the same LAN as you? Do you have physical access to it?

Thank you guys, Problem was solved with netburner tech support. The solution was as simple as adding a local port randomization mechanism.

Ed