IP masquerade is a kernel option within Linux to perform Network Address Translation. This means that it is possible to configure a Linux machine to dial an ISP and translate all TCP/IP device on an Ethernet interface to one PPP/SLIP address assigned by your ISP. However this only works for selected TCP/UDP protocols in earlier kernels and in later kernels ICMP i.e. ping.
Recompile Kernel with the following kernel options enabled: -