[Click] question about test-tun.click

[Xavier Brouckaert]

Hi,

I'm learning click and I'd like to use it. In test-tun.click, I see this
: ( http://www.pdos.lcs.mit.edu/click/ex/test-tun.html )
ch[0] -> IPPrint(tun-ok)
    -> IPFilter(allow icmp type echo)
    -> ICMPPingResponder
    -> IPPrint(tun-ping)      (*)
    -> tunq;

gav at osiris:~/Coding/click-1.4.1/conf$ sudo click test-tun.click
tun-ok: 1089295895.570164: 1.0.0.1 > 1.0.0.2: icmp: echo reply (0, 1)
tun-ok: 1089295896.580096: 1.0.0.1 > 1.0.0.2: icmp: echo reply (0, 2)
tun-ok: 1089295897.580098: 1.0.0.1 > 1.0.0.2: icmp: echo reply (0, 3)
tun-ok: 1089295898.580136: 1.0.0.1 > 1.0.0.2: icmp: echo reply (0, 4)
tun-ok: 1089295899.580051: 1.0.0.1 > 1.0.0.2: icmp: echo reply (0, 5)
tun-ok: 1089295900.580052: 1.0.0.1 > 1.0.0.2: icmp: echo reply (0, 6)
tun-ok: 1089295901.580228: 1.0.0.1 > 1.0.0.2: icmp: echo reply (0, 7)
tun-ok: 1089295902.580085: 1.0.0.1 > 1.0.0.2: icmp: echo reply (0, 8)

My question is : why do i never see a tun-ping message which should
correspond to the (*) line in the code ?

I know that it works OK with tethereal :
gav at osiris:~$ sudo tethereal -i tun0
Capturing on tun0
  0.000000      1.0.0.2 -> 1.0.0.1      ICMP Echo (ping) request
  0.000025      1.0.0.1 -> 1.0.0.2      ICMP Echo (ping) reply
  1.000043      1.0.0.2 -> 1.0.0.1      ICMP Echo (ping) request
  1.000067      1.0.0.1 -> 1.0.0.2      ICMP Echo (ping) reply
  1.999999      1.0.0.2 -> 1.0.0.1      ICMP Echo (ping) request
  2.000025      1.0.0.1 -> 1.0.0.2      ICMP Echo (ping) reply

So, I don't understand why the first IPPrint works and not the second.

Thank you for shedding light on this,
Xavier