5.8. Testing external MASQ ICMP forwarding

• Step Seven: Testing external MASQ ICMP forwarding

  From an internal MASQed computer, now ping a static TCP/IP address (NOT a machine by DNS name) out on the Internet (i.e. ping 152.19.254.81 (this technically the DNS name "metalab.unc.edu" which is home of MetaLabs' Linux Archive). If this works, it should look something like the result below and this ultimately shows that ICMP Masquerading is working properly. (hit Control-C to abort the ping):

  ------------------------------------- masq-client# ping 152.2.254.81 PING 12.13.14.15 (152.2.254.81): 56 data bytes 64 bytes from 152.2.254.81: icmp_seq=0 ttl=255 time=133.4 ms 64 bytes from 152.2.254.81: icmp_seq=1 ttl=255 time=132.5 ms 64 bytes from 152.2.254.81: icmp_seq=2 ttl=255 time=128.8 ms 64 bytes from 152.2.254.81: icmp_seq=3 ttl=255 time=132.2 ms ^C --- 152.2.254.81 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max = 128.8/131.7/133.4 ms -------------------------------------

  If it didn't work, again check your Internet connection. If this still doesn't work, make sure you are using the simple rc.firewall ruleset and that you have ICMP Masqurading compiled into the Linux kernel. Finally, make sure that the ruleset which enables IP MASQ is pointing to the correct EXTERNAL interface.