Re: How to listen to more a specific IP and specific ports

You need 4 sockets bound to each combination of IP address
and port (2 IP addresses times 2 ports amounts to 4 sockets
necessary). If the computer only has these two IP addresses
and you don't mind listening to the loopback address, you
can use two sockets with INADDR_ANY and the two specific
port numbers.

--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@xxxxxxxx
MVP VC FAQ: http://www.mvps.org/vcfaq
=====================================

"Bassam" <Bassam@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:77BD5E60-9D57-484E-830E-E5456812B472@xxxxxxxxxxxxxxxx
Dear all,
I am writing a network application that requires me to bind it to
specific network IP addresses and specific ports.

The normal binding resides in filling up the SOCKADDR_IN structure with
any
IP "INADDR_ANY" or a particular IP "192.168.1.148" and a single port as
follows:

SOCKADDR_IN tcpaddr;
int port = 1812;

tcpaddr.sin_family = AF_INET;
tcpaddr.sin_port = htons(port); //Single port
tcpaddr.sin_addr.s_addr = htonl(INADDR_ANY); //Any IP
or
tcpaddr.sin_addr.s_addr = htonl("192.168.1.148"); //A particular IP

Also this can be achieved by filling up the ADDRINFO structure of the
hints
parameter of the address resolution function "getaddrinfo()" as follows:

ADDRINFO hints;
LPADDRINFO resultPtr = NULL;

memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_PASSIVE; //to determin any IP
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;

getaddrinfo(NULL, "1812", &hints, &resultPtr);

The first argument of "getaddrinfo()" is NULL to determin that we are
willing to bind to any IP, and the second argument is a single port.

NOW: my question is how to listen to traffic coming through particular IPs
(i.e., "192.168.1.148" and "192.168.10.30") on the server machin and
particular ports 1812 and 1813 at the same time?

Do I need to bind my single socket handler to different SOCKADDR_IN
structures each has its own IP address and port no.. However, I find this
way
is not feasible because the particular IPs are not fixed. I mean sometime
I
need to listen to one or two or more particular IPs.

I would appreciate if you shed light on this matter.

Regards
Bassam


.

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