While deploying BFD on some ISR 4k's I noticed this "Session Host: Software". It turns out that BFD Echo mode is not hardware offloaded on these ISR 4K's, only the Control packets are. Although the echo packet is routed via CEF on the neighbor, when it comes back to us we process it in software. …
DMVPN NAT Explained
Here are all of the things you need to know about DMVPN and NAT. Hub: If the HUB must be behind a NAT, it can only be a static NAT, no PAT. If the HUB is behind a STATIC NAT, it must use IPSEC transport mode. If the HUB is behind a STATIC NAT …
Cisco Bundle vs Install Mode
Here's a quick post highlighting the most important fact about bundle vs install mode. Bundle mode (the old style of using a .bin and booting off of that), mounts the image in memory. Thus it uses up as much memory (RAM) as the image is in size. While install mode (the new style with packages.conf), …
How to route between VRFs on a Cisco router
This guide is the simplest way to route between 2 VRFs on a Cisco router. I didn't invent this method as someone showed it to me. Here's the GNS3 project + images if you want to follow along. https://upw.io/3uh/route-between-vrfs.gns3project Essentially IOU1 is the client with 192.168.1.1, and the default gateway is IOU2. IOU2 PATs …
Continue reading "How to route between VRFs on a Cisco router"
RDP error: This could be due to CredSSP encryption oracle remediation.
If you get this error, you need to create this registry key to fix it: You can either download the fix for the .reg file here or create it yourself with the code below RDP CRED SSP FIX REG FILE Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters] "AllowEncryptionOracle"=dword:00000002
Nexus 7k – show running-config aclmgr inactive-if-config for SVI ACL
I recently ran into an issue where I was preparing for a 7k ISSU. One of the first steps in the document from Cisco talks about running "show running-config aclmgr inactive-if-config". After I ran this I noticed that it listed an SVI with an ACL as inactive. After running "show interface vlan X" I saw …
Continue reading "Nexus 7k – show running-config aclmgr inactive-if-config for SVI ACL"