Cybersecurity

I posted my last post before I read the previous reply. I tried using iptables, and it seems to be not working on this box. I get an error message:
"...ip_tables.o: init_module: Device or resource busy" and that insmod failed on ip_tables.o. Note that ping, ssh, telnet and ftp connectoins are all accepted and work fine.

This followup might be useful for others who might be moving existing code from Windows. The IP ports issues were the least of my problems. I was porting this code from Windows. Win32 ignores the first parameter of the select() system call. I had n=1. In Linux that must be the *value* of the highest socket descriptor +1, *not* the number of sockets to be tested, or select will not return. Typically, that value would be reassigned anytime a new socket descriptor is allocated. That assumes that the system will allocate always-increasing socket descriptor values. I stuck INT_MAX in there and it works fine. It probably causes a little extra processing to traverse every possible socket descriptor value in the fd_sets, but it simplifies the code.

Thanks for the help.

Now what Language did you write this Socket w/ {PERL , C++ , etc};

Is the Program really listening? - use netstat.

What protocol is the program using - TCP , UDP?

See is you can telnet the port and get a possible socket hang - that indicates that something is listening.

Test locally on the running server before remotely /!\.