I'm reading this post: http://blog.serverfault.com/2011/09/30/the-stack-exchange-architecture-2011-edition-episode-1/

It seems you have 2 routers sitting in front of haproxy.

Are these 2 routers hardware based on linux routers?

What do they do, I would have thought things go straight to haproxy (or are they their because you have haproxy redundancy?)

  • If I recall, they're pfSense boxes, but I can't find the source of that at the moment, so it may be incorrect.
    – EEAA
    Commented Jan 16, 2012 at 20:44
  • You might be better of asking Zyper, KyleBrandt, or PeterGrace in Server Fault Chat. Usually, at least one of them is available there during the work day.
    – MDMarra
    Commented Jan 16, 2012 at 20:48
  • @ErikA - I have that feeing as well, but I can't recall why Commented Jan 16, 2012 at 20:48
  • Roto.
    – voretaq7
    Commented Jan 16, 2012 at 20:50

1 Answer 1


We currently have 2 Linux routers running on dedicated hardware (They are not VMs) in our primary NY Datacenter. Both our routers and load balancers are redundant with automatic failover (Both have had the primary fail, kernel panics if IIRC, and automatic failover did its job). These Linux routers also function as our firewalls.

We have them and not just our load balancers because we have many services in our datacenter that don't go through our load balancer.

We have some Cisco routers and firewalls that we have wanted to move to for a while but haven't had time for that project yet.

  • oh so you mean some requests bypass haproxy load balancers? and w/o haproxy, you wouldn't have the same level of control on traffic which pfSense gives you. Commented Jan 16, 2012 at 21:27
  • Well we have outbound traffic, fetching updates from the windows update example, so there is stuff that has no reason to go through haproxy (vpn connections would be another example). In terms of web requests however, they do all go through HAProxy off the top of my head. Commented Jan 16, 2012 at 21:33
  • Are cisco routers and firewalls expensive? (the ones you guys got) Commented Jan 16, 2012 at 22:01
  • Personally I would find them expensive, but they are not crazy in terms of our company. All the SAs know Cisco we there is less rampup. Certain things around Linux routers concern me, in particular their handling of certain BGP scenerios (quagga). BSD might solve those problems, a lot of people recommend it, but basically we were done "experimenting". Network redundancy gets complex fast when you want to cover more than just a single router totally going down. Commented Jan 16, 2012 at 22:10
  • what do you use for rate limiting? firewall or haproxy? this stuff is interesting, I def. need to readup up on tcp/ip again. Commented Jan 23, 2012 at 15:39

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