How can you force a web service client to use a specific port? - web-services

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.

Answer 2

In case someone else needs it, here is the Python code to do that:
#!/usr/bin/env python
from socket import *
import time
HOST = '**.**.**.**' # IP of the server
PORT = 8080
GET = '/hello/There'
BUFSIZ = 1024
ADDR = (HOST, PORT)
sock = socket(AF_INET, SOCK_STREAM)
sock.bind(('',4925))
sock.connect(ADDR)
print 'connected'
request = """GET %s HTTP/1.0\n
Host: %s\n
User-Agent: Python\n
\n""" % (GET, HOST)
sock.send(request)
data = sock.recv(1024)
string = ""
while len(data):
string = string + data
data = sock.recv(1024)
print string
sock.close()
This is working with a wsgi server running on the other side. Pretty straight forward. Thanks for the help.