FWIW this is what I use.
You can find it on ebay etc.
Not cheap, but very effective.
I paid around $39 for 1 pint which will make about 16 one gallon mixes.
It works on my outside cameras for about a month and a half at each spraying.
Less if exposed to rain. (I spray a band around the cameras)
I mix it at 1 oz. per gallon for outside spray and 3/4 oz. for inside in the garage.
The mix is a little thicker than just water alone and needs to be shaken before each use.
(Edit: Just to mention the obvious. Do NOT get spray in your Ethernet or power connectors)
Rich
Deltamethrin
D-Fense SC and Suspend SC both contain 4.75% Deltamethrin.
This odorless insecticide is in a micro encapsulated formulation that gives you up to 3 months of continuous pest control indoors, and 1 month or better on the outside surface of your home or business. D-Fense SC and Suspend SC both contain 4.75% Deltamethrin.
Considered by many professionals to be the best insecticide to kill spiders, scorpions, large roaches and other labeled insect pests
Deltamethrin insecticide sprays used to control or eliminate a wide variety of pests such as spiders, bed bugs, ants, carpenter ants, fleas, ticks, clothes moths and many other household pests.
Using 1.5 ounces of concentrated Deltamethrin product per gallon of water is considered the "clean out" rate by professionals.
The clean out rate has better knock down power for spiders, ticks and other hard to kill pests in and around the home.
Once pest populations are eliminated, use .750 ounces per gallon for regular spray treatment.
When used as directed, this Deltamethrin spray is perfectly safe for use in homes where children and pets live.
Keep children and pets out of area to be treated and keep them off treated surfaces until surfaces have been allowed to dry.