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.
Causes. 1  Main Causes. Muscle spasms cramps and strained muscles overuse account for most leg pain. 2  Muscle Cramps. Brief pains 1 to 15 minutes are often due to muscle spasms cramps. 3  Muscle Overuse Strained Muscles. Constant leg pains are often from hard work or sports.  Growing Pains. 10% of healthy children have harmless leg pains that come and go.