https://networknet.nl/tags/ipv4/Recent content in IPv4 on Ivan Versluis — NetworknetHugoenWed, 04 Nov 2026 13:55:12 +0100https://networknet.nl/snippets/public-egress-ip/Wed, 04 Nov 2026 12:00:00 +0100https://networknet.nl/snippets/public-egress-ip/<p>When I troubleshoot connectivity in enterprise networks, I want to know which public address an external service sees. I run this command from my terminal:</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-sh" data-lang="sh"><span class="line"><span class="cl">curl -4 ifconfig.io </span></span></code></pre></div><p>When I need to check IPv6 egress, I use:</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-sh" data-lang="sh"><span class="line"><span class="cl">curl -6 ifconfig.io </span></span></code></pre></div><p>The <code>-4</code> and <code>-6</code> flags select the connection address family. They do not modify the response.</p> <h2 id="why-i-use-it">Why I use it</h2> <p>My outbound traffic may pass through NAT gateways, HTTP proxies, VPNs or other security appliances. The address returned by <strong>ifconfig.io</strong> is the public IP seen by that service, which may differ from my workstation&rsquo;s address. If curl uses an HTTP proxy, I may see the proxy&rsquo;s address.</p>