Documentation

Connect to a server with a different IP or Hostname (aka. DNS Spoofing)
- What is DNS SPoofing?
  - When can it be useful?
- DNS Spoofing with Paw
  - Configure your request
  - Example

Connect to a server with a different IP or Hostname (aka. DNS Spoofing)¶

Get the most of Paw
DNS SPoofing

SSL Client Certificates
Use invalid SSL certificates
HTTP libraries
Internationalized domain names

What is DNS SPoofing?¶

Let’s say you want to access http://paw.cloud/test on Server A, and the domain name paw.cloud is pointing to Server B (not Server A). Then, what you need is to connect to Server A while sending an HTTP Header Host: paw.cloud.

In fact, many web servers have the notion of virtual hosts or server blocks (Apache Virtual Hosts, Nginx Server Blocks), so when a request is handled, the response will depend on the HTTP Host header.

Most, if not all, web browsers and HTTP libraries automatically set that header for you depending on the URL you’ve set (if URL is http://echo.paw.cloud/test, host will be echo.paw.cloud). Of course Paw sends it automatically too, but you have the ability to override it.

When can it be useful?¶

Well, it’s up to your needs! There are 2 main cases:

You are testing a new server, and you didn’t point your domain name to that new server yet. You want to know how the server will react when its visitors/API consumers will access that through the main domain name.

Your web service is running in a cloud infrastructure, behind a load balancer. Then your domain name is pointing to the load balancer which forwards requests to the appropriate server. To test a specific server, avoiding the load balancer, you’ll have to connect to the server’s IP address or hostname (e.g. ec2-111-111-111-111.compute-1.amazonaws.com if you’re running on Amazon EC2), while pretending to connect to the main domain name, using the Host HTTP header.

DNS Spoofing with Paw¶

Configure your request¶

Paw will connect to the hostname (or IP address) specified in the URL field, and the Host header will be set to this hostname, unless you manually set a Host header. To connect to a different hostname, you need to specify the actual IP or host of the server you want to connect to in the URL field (e.g. http://server-to-connect-to/path/to/resource) and manually set the Host of the server you are pretending to connect to.

Secure HTTPS requests will use the Host header for certificate trust and Server Name Indication (SNI).

Example¶

We want to access http://paw.cloud/paw on the server ec2-111-111-111-111.compute-1.amazonaws.com:

Set the URL field: http://ec2-111-111-111-111.compute-1.amazonaws.com/paw

Add an HTTP Header Host and set its value to paw.cloud

That’s all done!

The server ec2-111-111-111-111.compute-1.amazonaws.com will be asked to serve the page /paw for the host paw.cloud.