goDNSreroute

goDNSreroute is a tool for developers to capture and re-route DNS queries for network testing

Background

The concept of a redirecting DNS server for the purpose of testing is derived from the dns-reroute project by nanoscopic. The DNS server portion of this project borrows heavily from code located here.

Introduction

goDNSreroute captures and re-routes DNS queries for specified domains. For domains not specified, goDNSreroute hands off the query to a typical DNS server (8.8.8.8 by default). This allows the user to re-route DNS queries for network testing while not affecting network connectivity otherwise.

Usage

At the top of main.go are three variables used to configure goDNSreroute server:

• dnsPort: Specifies the port which goDNSreroute listens. DNS servers typically listen on port 53. Considering this is well-within the reserved port range (0-1024), it is often helpful to be able to run this server on an unreserved port (>1024).
• dnsLookupServer: Specifies the upstream DNS server for domians not listed in domainsToAddresses. This allows DNS quries not listed in domainsToAddresses to be resolved correctly.
• domainsToAddresses: List of domain names and IP addresses to re-route.

DNS resolution can be tested with dig. Examples below:

• dig @{DNS server IP} -p {DNS server port} {domain to look up}
• dig @127.0.0.1 -p 5354 google.com