Practice Not Theory
On March 6th, I will be hosting an Advanced Cisco ACI event where I will cover the benefits of Cisco ACI, go over real-world Cisco ACI Fabric and Tenant naming conventions, review brownfield migration strategies and demo how easy it is to inject firewalls to inspect traffic between migrated networks. In addition, we will also have our Cisco Learning Partner that will provide a Cisco ACI training.
https://lp.cdillc.com/2020-3-6-hcaf-avengers-aci-registration.html
With most Cisco routing platforms, by default, routers do not advertise network prefixes to eBGP peers whose AS is already found last in the BGP’s network prefix AS_PATH attribute. This is a loop prevention mechanism known as disable-peer-as-check.
Recently I deployed a number of Fortigate Fortinet firewalls within Cisco ACI and noticed that Fortigates (with code 5.6) do not have any option of enabling this feature. I was actually surprised because even Palo Alto firewalls have this as an option. In Palo Alto, this option is known as “Enable Sender Side Loop Detection” and its found directly under the neighbor configuration. When you deploy a lot of VRFs with BGP in ACI, this is an option you need to be aware of.