Layer 3 Switch instead of router?

This might be a stupid questions, but I've have heard people using a Managed Layer 3 Switch instead of a standard router to the WAN. Obviously, there is a risk of security on Switch intself being that the external ip address would be configured on the switch. Therfore, making the switch vurnable to attackers.

Any thoughts on this?

Three thoughts spring to mind here:
1) A layer-3 switch is meant to perform routing between VLANs. So unless you need VLANs in your network you're adding complexity for no reason
2) A switch probably won't have the necessary WAN-type interfaces that a router would be able to provide
3) Switches are for switching really. I'd have thought that if you really want to do routing properly they you'd be best getting a device that was designed to do just that

i agree with bishop, you will not be having many WAN options on a layer 3 switch, and it would make things unnecessarily complicated.

3) Switches are for switching really. I'd have thought that if you really want to do routing properly they you'd be best getting a device that was designed to do just that

However, if you are on a tight budget and you're hand off from your provider is ethernet (copper or fiber), a layer-3 switch can be a good option and can be configured to only allow access from specified networks.

We are using a number of Cisco 3550's with the EMI image to link multiple Motorola Canopy AP sites back to the core. Our requirements called for high-performance inter-vlan routing in a small form factor, so the 3550s fit the bill nicely. We tried using a Soekris 4851 with 7 interfaces running Zebra. The functionality was there, but the performance was not quite good enough for our purposes.

Absolutely agree. Use what you've got - we do it all the time. But if you have an open field and a reasonable budget there's no substitute for doing things the proper way

Three thoughts spring to mind here:
1) A layer-3 switch is meant to perform routing between VLANs. So unless you need VLANs in your network you're adding complexity for no reason
2) A switch probably won't have the necessary WAN-type interfaces that a router would be able to provide
3) Switches are for switching really. I'd have thought that if you really want to do routing properly they you'd be best getting a device that was designed to do just that

Disagree with bishop. a router is a device made specifically for routing, and a switch for bridging, two concepts quite different.

So in legacy routing devices the only device that can perform routing was a router.

Now the layer 3 switch, a device made specifically for switching, and routing also, performs better than an only router device, why??
If it is Cisco it routes by CEF in hardware, so more throughput and faster packet handling than a router, a Router performs routing in software.

Thats why a multilayer switch is more expencive than a router, you have both jobs (routing and switching) in only one device.

So I recommend you a multiler switch if you can.