Slow address translation in small business network

Question

Here at my office we've started to experience a slow down for browsing websites due to our router becoming bogged down by the the traffic. I've narrowed it down to the router as the problem goes away temporarily anytime the router is unplugged and plugged back in.

Current network configuration

Comcast SMB cable modem
Linksys consumer grade router
Win2k3 Server Domain Controller + DNS
30-50 connected workstation clients

The router was originally added to the equation due to the previous modem that was from comcast not being able to support the address translation workload back then before we upgraded our internet and received the new SMB modem.

My question is what is the most appropriate solution for this, is it worth investigating whether the current modem is powerful enough to be the router itself, should we just buy a business class router, or is there a role available for Win2k3 to handle this?

Answer 1

I've seen this exact same issue on a Soekris router we once used. Rebooting it always fixed our issue in the short term but then it would slow down again. Your router definitely can't keep up. You're network is probably fine, it's your router that is the bottleneck.

We use a Cisco ASA 5505 for one of our remote offices that supports about 80 users. We've been very happy with this device. Cisco has come a long ways with their support as well. This device has a GUI if you don't have experience with ssh/telnet for configuring them.

What's more, Cisco techs will set up the device for you within the first 90 days of purchase. The extended support isn't much if you want to go longer (we did). You'll probably want to get an unlimited user bundle for that device. It'll run you around $600 but seriously, the Cisco techs will save you a ton of heartbreak since they'll set it up for you. ROI on the support will pay off.

FYI, I have a Cisco certification and still use tech support from time to time.

Answer 2

You might want to find out if the router is just being overburdened, in which case you should investigate getting a higher end router from Cisco instead of a SOHO-class router, or configuring a Linux system to act as your router, or finding out if there's something flooding your network that is killing your router's available memory for routing.

I'd suspect with up to 50 machines if this seems to happen periodically that you're simply pumping too much traffic through it for a SOHO router to handle.

I personally might look at getting a spare machine with a couple NIC's and turning it into a router/firewall. Either a custom linux job so that you could run NTOP on it for monitoring network usage (and possibly track abuse) and other such tools, or something like Smoothwall as a dedicate "router/firewall appliance". This should alleviate your routing headaches as well as give you a large number of options for tracking and troubleshooting issues, plus it's cheaper than a cisco solution for a small to medium 50-machine business.