Linux IP Masquerade HOWTO
Prev | Chapter 5. Testing IP Masquerade | Next

# 5.3. Testing internal MASQ client to MASQ server connectivity

- Step Three: Testing internal MASQ client to MASQ server connectivity

  Next, from the same internal MASQed computer, try pinging the the IP address of the Linux MASQ server's INTERNAL interface (i.e. ping 192.168.0.1 ). This will verify that TCP/IP is correctly working on both the local and Linux MASQ machine. Almost ALL modern operating systems have built-in support for the "ping" command. If this ping doesn't work, make sure that TCP/IP is correctly configured on the MASQed Server as described by the various Network HOWTOs (URLs can be found in the requirements section for your 2.4.x kernel in Section 2.6, 2.2.x kernel in Section 2.7, or 2.0.x kernel in Section 2.8). The output should look something like the following (hit Control-C to abort the ping):

      ------------------------------------
      masq-client# ping 192.168.0.1
      PING 192.168.0.1 (192.168.0.1): 56 data bytes
      64 bytes from 192.168.0.1: icmp_seq=0 ttl=255 time=0.8 ms
      64 bytes from 192.168.0.1: icmp_seq=1 ttl=255 time=0.4 ms
      64 bytes from 192.168.0.1: icmp_seq=2 ttl=255 time=0.4 ms
      64 bytes from 192.168.0.1: icmp_seq=3 ttl=255 time=0.5 ms
      ^C

      --- 192.168.0.1 ping statistics ---
      4 packets transmitted, 4 packets received, 0% packet loss
      round-trip min/avg/max = 0.4/0.5/0.8 ms
      ------------------------------------

  If the ping failed, check the network connection between the MASQ server and the PC. If it's a DIRECT Ethernet connection (no hub or switch), you MUST have a "Ethernet cross-over cable". These cables are common and can be found at any computer store. Without this cable, the NICs (network cards) will not give you a "LINK" light. If you are using a hub or switch, make sure the ports connected to the MASQ server and MASQed client machine have a LINK light. If they do and the pings STILL don't work or there is a lot of packet loss, try different ports on the hub/switch (it not all that uncommon to have hub/switch ports die). Finally, if things still don't work perfectly, try replacing each of the NICs in the machines. You would be surprised how many people I've helped have found that their NIC cards were going bad and caused them all kinds of grief.

Prev | Home | Next
Testing internal MASQ client PC connectivity | Up | Testing internal MASQ server connectivity