https://fy.ax/tags/cisco/Recent content in Cisco on Code RedHugoenSun, 22 Mar 2026 01:30:00 +0300https://fy.ax/posts/panos-gre-over-ipsec-with-cisco-iosxe/Sun, 22 Mar 2026 01:30:00 +0300https://fy.ax/posts/panos-gre-over-ipsec-with-cisco-iosxe/<p>If you&rsquo;ve ever needed to set up a GRE-over-IPSec tunnel between a Palo Alto firewall and a Cisco router, you&rsquo;ve probably noticed the documentation is thin on the ground — especially when it comes to interoperability between the two platforms. I recently went through this exercise between a <strong>PA-VM (PAN-OS 11.2.5)</strong> and a <strong>Cisco CSRv-8000 (IOS-XE 17.16.1a)</strong> and learned some things the hard way.</p> <h2 id="the-goal"> The Goal <a class="heading-link" href="#the-goal"> <i class="fa-solid fa-link" aria-hidden="true" title="Link to heading"></i> <span class="sr-only">Link to heading</span> </a> </h2> <p>Replicate a production pattern where a customer device connects to a target router using <strong>GRE tunnels encapsulated inside IPSec</strong> — the same architecture used in financial trading networks where encrypted, routed tunnels carry sensitive traffic between sites.</p>