The new Cisco IOS Firewall for Internet Protocol version 6 (IPv6) provides stateful inspection to both existing IPv4 and IPv6 traffic on a single interface for enhanced performance, along with better management of the IPv6 migration process.
Causes of Muscle contractions that are rare. The offical US government definition of a rare disease is one that affects 200,000 people or less. The following causes of Muscle contractions appear in the population at a rate of less than 200,000 people per year in the USA: 1  Alpers Syndrome-involuntary muscle contraction. 2  Fahr's Syndrome-athetosis. 3  Ramsay Hunt syndrome Type II-involuntary muscle contraction.
Other causes can include medications such as birth control, diuretics (which are often prescribed for people with high blood pressure) and steroids. A lack of potassium or calcium can also be the underlying cause, as well as cold weather.. Acute leg cramps frequently are confused with restless legs syndrome (RLS). But RLS is a different and more serious, chronic condition characterized by discomfort and persistent throbbing and pulling sensations in the legs. How to Prevent Leg Cramps. There are a number ways you can alleviate nighttime leg cramps.