NuGet proxy settings

This post is based on code present in NuGet 2.0.

NuGet reads web proxy settings from three distinct sources, in order:

• configuration files
• environment variables
• current user's Internet Options

While the layout of IE's Connection Settings is probably familiar to you if you are behind a corporate firewall and require proxy configuration to access the Internet, first two options require a bit of explanation.

For configuration files, NuGet first considers .nuget\NuGet.config and then falls back to %APPDATA%\NuGet\NuGet.config. Relevant configuration entries are http_proxy, http_proxy.user and http_proxy.password. You can either edit them manually, by adding a line under <settings> node:

<add key="http_proxy" value="http://company-squid:3128" />

or you can add them from NuGet command line:

nuget.exe config -set http_proxy=http://company-squid:3128

If those variables aren't found in the configuration files, NuGet will fall back to checking standard environment variables for proxy configuration. By pure concidence, the variables have the same names as the configuration options ;-) . Names are not case-sensitive, but you might have to experiment a bit until you get NuGet to properly parse your settings if you have a space where it wouldn't expect one (e.g. in your user name).

Finally, if you are running NuGet in your user account, not using a service account (e.g. on a continuous build server), it will simply pick up whatever you have configured in the Control Panel as the system proxy server. All credentials configured there (including Active Directory single sign-on mechanism) should work without any work on your part.