Software⏱️ 2 min read📅 2026-06-03

How to Fix: How do I update Ruby Gems from behind a Proxy (ISA-NTLM)

Update Ruby Gems behind Microsoft ISA server in NTLM-only mode.

Quick Answer: Use the `http_proxy` option when installing or updating gems, e.g. `gem install http://your-proxy.com/rubygems`.

To update Ruby Gems from behind a Proxy (ISA-NTLM), you'll need to configure the `http_proxy` and `https_proxy` environment variables. This can be achieved using the `rubysspi` gem or by manually modifying your system's proxy settings.

🛑 Root Causes of the Error

  • The `rubysspi` gem may not work due to ISA server's NTLM-only mode, which prevents it from authenticating with the proxy.

🔧 Proven Troubleshooting Steps

Method 1: Environment Variable Configuration

  1. Step 1: Set the `http_proxy` and `https_proxy` environment variables to your proxy server's URL. For example, if your proxy server is `https://my-proxy-server:8080`, set the variables as follows:

Method 2: Ruby SSPI Configuration

  1. Step 1: Install the `rubysspi` gem using Bundler or by running `gem install rubysspi` in your terminal. Then, add the following lines to your `~/.bashrc` file (or equivalent):

By configuring these environment variables or adding the `rubysspi` gem configuration, you should be able to update Ruby Gems successfully from behind your ISA server's proxy.

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