How to Turn on IP Forwardarding

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IP Forwarding
  • Effectively makes a Linux box act as a router

  • Is usually used with two network interfaces (one internal, and one external)

  • Can be used with firewall services and is often used for NAT


Steps to Turn on IP Forwarding


 1) Modify /etc/sysctl.conf
     vi /etc/sysctl.conf
     add this line:
     inet.ipv4.ip_forward=1
 2) Make the Change Active
     sysctl -p
 3) To View Current Settings:
     sysctl -a | grep ipv4


More info can be found on the redhat site:
https://www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/security-guide/s1-firewall-ipt-fwd.html


We'll leave firewall rules for another topic...

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