LSP problem

[chaitresh]

Hi all,

I am working on a LSP firewall similar to ZoneAlarm. It basically intercepts any application that uses winsock to access the Internet, and the user can decide to allow or deny access to the Internet. But the application breaks quite often, without any pattern, and refuses access to the Internet. I found that the break of service is due to the name lookup failure such as gethostbyname().

Example:
I run the firewall. Run IE for surfing. Allow IE access to the Internet in the firewall. Go through normal user behavior of opening bunch of IE windows and closing them, till the firewall crashes. At this point if I type the IP address of the URL I intend to go to, then IE works, but typing the host name like www.yahoo.com fails. Obviously the access to the DNS is blocked at this point.

I would appreciate any help here.
Thank you.

CS

[shalomb]

You say you are writing a firewall, well you have to make sure that certain port numbers have no restrictions on them for example port 53 which is meant for DNS.
If this port is blocked, you will be unable to resolve host names to ip address and vice-versa. So make sure that this port is open when it needs to be.
I am not much of a programmer and dont really know what the method gethostbyname() does(is it generic or user-defined). I basically say that you havent given us enough details for us to troubleshoot this further.
What about applications that do not use winsock?