NAT is one of the many problems that VoIP has which causes one way audio, call being dropped and clients becoming unreachable. People have devised many ways other than asterisk to overcome the problem and there fore here in this article I discuss about using Asterisk with clients (SIP phones ) behind NAT.
Installing asterisk on Ubuntu is very easy, its a sequence of some simple commands.
Stock Ubuntu doesn't ship some with the packages that are required to compile Asterisk. First let's install those packages.
#apt-get install build-essential
#apt-get install linux-headers-`uname -r`
#apt-get install libssl-dev
#apt-get install ncurses-dev
#apt-get install libnewt-dev
#apt-get install zlib1g-dev
#apt-get install bison