Using sed command to search and replace IP address 

" If your version of sed supports extended regular expressions (the -r option), you could do something like this (which is similar to what you have in your grep statement). Also note $newip is outside the single quotes to allow the shell to replace it.

sed -r 's/(\b[0-9]{1,3}\.){3}[0-9]{1,3}\b'/$newip/

BTW this solution still matches strings that do not represent IP addresses. See this site under IP Adresses for more complex solutions."
 มีข้อเสียคือมัน replace pattern เลข.เลข.เลข.เลข ไม่ได้สนใจว่าเป็น IP address ที่ถูกต้องหรือไม่

from: StackOverflow using-sed-to-search-and-replace-an-ip-address-in-a-file

Browse internet anonymously with Ubuntu (free yourself from limited network)

Browse internet anonymously with Ubuntu (free yourself from limited network)

1. Open a terminal then execute the command (leave it during your internet surfing)

#ssh -ND 9999 username@home_router_ip_address

i.e.: ssh -ND 9999 daho@homeip_addr

2. Open the proxy setting (gnome proxy settings or Firefox proxy setting)

input only address of socks v5 proxy
127.0.0.1 port 9999

input none and port 0 to the others



original post:
http://www.searchmarked.com/ubuntu/how-to-surf-anonymously-using-an-ssh-tunnel-and-ubuntu.php

More options of SSH Tunneling
https://help.ubuntu.com/community/SSH/OpenSSH/PortForwarding