I would start with a simple unmanaged ethernet switch. They much prefer cold than hot. If you are set on it being labled for a temperature range, look for an industrial ethernet switch. They are pricier, mostly likely require a seperate 24vdc power source, but in my experience are fairly bulletproof. I ran my grain PLC system with $8 netgear switches for 2 years until lightning took out a couple of ports on the cheap switches. I replaced them with some used industrial switches off ebay. The fact that they were DIN mounted excited me as much as anything.

As for distance. 100 meters is the spec. Regular cat 5 or 6 cable will work farther than that as long as the bandwidth isn't too large. Your results may vary though. If you really need to be further than that, look into an ethernet extender. Here is a link to some from Startech.  

http://www.amazon.com/StarTech-com-VDSL2-Ethernet-Extender-Single/dp/B002CLKFTG/ref=sr_1_5?ie=UTF8&qid=1428796257&sr=8-5&keywords=ethernet+extender 

My house is about a 1/4 mile from the office.  My dad buried at 14/2 UF wire back in the 70's when he lived there to get a 2way radio base station in the house.  I have a pair of these setup over that wire to run ethernet from the office to my house.  I keep a pair on hand as they don't like lightning at that distance, but the last set has been in service for quite a while.