Domain 4 — Routing 20 cards
What is the default administrative distance of a static route on FortiGate?
10 — not 1. This is a common Cisco-habit mistake.
What does administrative DISTANCE decide?
Which route gets installed into the routing table in the first place.
What does route PRIORITY decide, and which value wins?
It breaks ties among routes already in the table with EQUAL distance. LOWER priority wins.
Where does route METRIC apply?
Only within a dynamic routing protocol.
What two conditions produce ECMP?
Equal administrative distance AND equal priority.
What is the default ECMP load-balancing method?
source-ip-based
Name the four ECMP load-balancing methods.
source-ip-based (default) · source-dest-ip-based · weighted-load-balance · usage-based (spillover)
Why pair a blackhole route with a route-based IPsec tunnel?
So traffic does not leak out the default route when the tunnel drops. Give the blackhole a HIGHER distance than the tunnel route.
Are policy routes evaluated before or after the routing table?
Before.
What is the DEFAULT reverse path forwarding mode, and what does it check?
Loose (feasible). The source IP just has to be reachable via ANY route out ANY interface.
What does STRICT RPF check, and how do you enable it?
The best route back to the source must use the same interface the packet arrived on. · · config system settings → set strict-src-check enable
An SD-WAN member is healthy but no rule will select it. What is missing?
A static default route pointing at the sd-wan virtual interface. No route, no selection.
Name the SD-WAN performance SLA probe protocols.
Ping, HTTP, HTTPS, DNS, TCP-echo, UDP-echo, and TWAMP.
Which three metrics does an SD-WAN performance SLA measure?
Latency, jitter, and packet loss. Minimum bandwidth is optional.
Name the four SD-WAN rule strategies.
Manual · Best Quality · Lowest Cost (SLA) · Maximize Bandwidth (SLA)
What does the Lowest Cost (SLA) strategy do?
Among the members currently MEETING the SLA, it picks the lowest-cost (priority) one. The usual production choice.
What is the evaluation order: routing table, SD-WAN rules, policy routes?
Policy routes → SD-WAN rules → routing table.
What does the implicit SD-WAN rule at the bottom do by default?
Load-balances across all members using source IP.
An SLA shows state(alive) but the service shows no members. Why?
The link is up but is not MEETING the SLA targets. Alive does not mean eligible.
Which command shows the actual forwarding table rather than the RIB?
get router info kernel