With clever, dynamic routing protocols (RIP, EIGRP, OSPF et al) being able to learn routes all by themselves, and even adapt to network problems by re-routing traffic when a link goes down, why would you even bother using boring old Static routes to get your packets to their destination?
Well, in defence of Static routes here are few reasons why you might use them:
- It’s all gone a bit runny – your super-duper dynamic routing protocols have let you down, you can’t figure it out quickly and are in danger of being fired, unless…….you whack in a quick static route and bingo – all is good again and you can figure out the issue while your heart rate drops back to normal.
- You might sleep better at night – if you’re a control freak and can’t bear the thought of anything happening without your say so on your precious network, then Static routes can help.
- To give your router a break – you may have an old, creaking router that can barely send a packet on it’s way, never mind run a fancy dynamic routing protocol with all it’s processing overhead.
- Keep it simple – you simply don’t have that much routing going on in your network, so perhaps dynamic routing is overkill.
- You need a backup – dynamic routing with all it’s built in resilience not enough for you? Bung in a Floating Static route for good measure. With it’s AD set to higher than that of any dynamic protocols, it’ll only kick in if your dynamically learned routes drop out of the routing table.
- There’s nowhere else to go – if your router has no idea how to get a packet to it’s next hop, then rather than just drop the packet it will give it a fighting chance and send it on to the router’s “gateway of last resort” AKA a Default Static route.
Configuring Static Routes
A Static route to network 192.168.10.0/24 network via a next hop IP address 10.0.0.1:
Router(config)#ip route 192.168.10.0 255.255.255.0 10.0.0.1
A Static route to network 192.168.10.0/24 network via local interface fastEthernet 0/1:
Router(config)#ip route 192.168.10.0 255.255.255.0 fastEthernet 0/1
A Floating Static route to network 192.168.10.0/24 via next hop IP address 10.0.0.1 with an AD of 200:
Router(config)#ip route 192.168.10.0 255.255.255.0 10.0.0.1 200
A Default Static route via next hop IP address 10.0.0.1:
Router(config)#ip route 0.0.0.0 0.0.0.0 10.0.0.1
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