Okay, so the other day I was dealing with a bit of a headache. I needed to set up my Juniper router to handle traffic going out to the internet. The thing is, I had two internet connections from different providers, and I wanted to make sure the traffic was balanced between them. That’s where filter-based forwarding, or FBF, comes into play.
I started by digging into the router’s configuration. First thing I did was create a new routing instance. Think of it like a separate virtual router within the main one. I gave it the type ‘virtual-router’ and assigned one of my interfaces, `pp0.1`, to it. This way, I could manage traffic going through this interface independently. I made sure to set up the necessary routes in both the main routing instance and this new virtual one, so everything knew where to go.
Next, I dove into the firewall filter part. This is where the magic happens. I crafted a filter that looked at the source address of incoming packets. Based on that address, I defined rules to direct traffic to either one of my internet connections. This is how I achieved the load balancing. For example, if a packet came from a certain IP range, I’d send it out through one connection, and if it came from another range, it went out the other. Simple, right?
I applied this filter to the interface that was handling the incoming traffic. Now, whenever a packet arrived, the router would check the filter rules, figure out which routing instance to use, and then send the packet on its way. It’s like having a traffic cop inside the router, directing each packet to the right destination.
- Step 1: Created a ‘virtual-router’ type routing instance.
- Step 2: Put interface `pp0.1` into the new routing instance.
- Step 3: Configured routes in both the main and virtual routing instances.
- Step 4: Created a firewall filter to inspect source addresses.
- Step 5: Defined rules in the filter to direct traffic based on source address.
- Step 6: Applied the filter to the incoming traffic interface.
After setting everything up, I did some testing. I sent traffic from different source addresses and watched as it flowed out through both internet connections. The load balancing was working perfectly! Each connection was getting its fair share of the traffic, and I could even see it in the router’s monitoring tools. It felt good to see it all come together.
Of course, this setup also gives me some redundancy. If one of the internet connections goes down, the router will automatically send all traffic through the remaining one. No more downtime, which is a huge relief.
It wasn’t too tough, in the end. It’s amazing how you can use these simple building blocks like routing instances and firewall filters to create a pretty robust solution. Now my network is humming along nicely, and I’ve got that sweet, sweet load-balanced internet connection. It’s a good feeling.
