Question

Is it possible to force an web service client to talk from a specific range of port E.g. 4900- 4999 to a web server in port 80?

I understand now that there is client and server port numbers and need to create a client application to send http statuses to a web server but firewall team only opens ports 4900 to 4999 in the client.

Any ideas?

Answer 1

If you are using a web browser to connect to your server then you may be out of luck but as you said in your question that you are creating a client application you can do this with the bind system call in both Windows and Linux (this code is in C):

struct sockaddr_in client;

sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);

memset(&client, 0, sizeof(client));
client.sin_family = AF_INET;
client.sin_addr.s_addr = htonl(INADDR_ANY);
client.sin_port = htons(4901);

Then call bind:

res = bind(sock, (struct sockaddr *)&client, sizeof(client));

If this call is successful (res is 0) you can then connect your socket to the server and you will be connecting from port 4901.