how to listen the packets coming out from the yun

hi

so.. this is more a curiosity/obession for see what really happens then a real need.

I'm not so proficient in the network thing but I'm looking for a way to listen (or sniff) the packets that are coming out from the yun via wifi.

from the arduino code in the yun I'm sending some packages via

HttpClient client;
// ...
client.get(url);

I would like to see somewhere that the packets really goes out of the yun.
How is it possible to do it?

If it worse I have an openwrt router.

After a little googling I've found this "tcpdump" thing but I don't find the binaries in the opkg install.. so, any advice?

opkg list |grep tcpdump
opkg install tcpdump
tcpdump -XX -i eth1 port 80
         0x01f0:  6774 683a 2034 3733 0d0a 0d0a 7067 705f  gth:.473....pgp_
        0x0200:  6d65 7373 6167 653d 2d2d 2d2d 2d42 4547  message=-----BEG
        0x0210:  494e 2b50 4750 2b4d 4553 5341 4745 2d2d  IN+PGP+MESSAGE--
        0x0220:  2d2d 2d25 3044 2530 4156 6572 7369 6f6e  ---%0D%0AVersion
        0x0230:  2533 412b 6861 6e65 5749 4e2b 4a61 7661  %3A+haneWIN+Java
        0x0240:  7363 7269 7074 5047 2b76 322e 3025 3044  scriptPG+v2.0%0D
        0x0250:  2530 4125 3044 2530 4168 4977 4454 506c  %0A%0D%0AhIwDTPl
        0x0260:  7477 4b56 4e79 4d41 4241 2532 4639 6b6c  twKVNyMABA%2F9kl
        0x0270:  5478 7753 6e39 5936 5372 4e68 5554 3734  TxwSn9Y6SrNhUT74
        0x0280:  696e 6732 5654 5152 424d 756a 4f35 5035  ing2VTQRBMujO5P5
        0x0290:  6834 4671 346c 4925 3044 2530 4167 4c34  h4Fq4lI%0D%0AgL4
        0x02a0:  4959 4271 456c 6141 3979 646d 3967 334e  IYBqElaA9ydm9g3N
        0x02b0:  3325 3246 7774 4f65 6d6b 614e 3238 4370  3%2FwtOemkaN28Cp
        0x02c0:  4d70 3177 3137 7232 6659 3857 5163 7771  Mp1w17r2fY8WQcwq
        0x02d0:  7232 5045 3567 7978 7754 7325 3044 2530  r2PE5gyxwTs%0D%0
        0x02e0:  4156 5153 4774 6f48 6773 5667 3855 6c71  AVQSGtoHgsVg8Ulq
        0x02f0:  4945 7065 7777 5947 716b 4d71 5939 4b57  IEpewwYGqkMqY9KW
        0x0300:  584d 5a36 536e 666c 4e51 4e73 6c36 656d  XMZ6SnflNQNsl6em
        0x0310:  4f58 7568 3072 3237 6d5a 4f61 4225 3044  OXuh0r27mZOaB%0D
        0x0320:  2530 4146 4425 3246 526c 4a4d 645a 6152  %0AFD%2FRlJMdZaR
        0x0330:  4749 7a52 354a 7766 644a 4c49 3330 4278  GIzR5JwfdJLI30Bx
        0x0340:  3379 2532 4271 4153 6149 3455 316a 6574  3y%2BqASaI4U1jet
        0x0350:  6c67 7355 4d58 4e41 7059 694e 6f31 5374  lgsUMXNApYiNo1St
        0x0360:  5257 3925 3044 2530 414c 3159 476d 5972  RW9%0D%0AL1YGmYr
        0x0370:  4c37 5978 516f 5778 7632 6a74 6c59 7737  L7YxQoWxv2jtlYw7
        0x0380:  2532 4250 6f5a 7832 526a 4c69 2532 4647  %2BPoZx2RjLi%2FG
        0x0390:  6445 744b 4425 3242 6661 5167 5125 3344  dEtKD%2BfaQgQ%3D
        0x03a0:  2533 4425 3044 2530 4125 3344 6353 3834  %3D%0D%0A%3DcS84
        0x03b0:  2530 4425 3041 2d2d 2d2d 2d45 4e44 2b50  %0D%0A-----END+P
        0x03c0:  4750 2b4d 4553 5341 4745 2d2d 2d2d 2d25  GP+MESSAGE-----%

for wifi port:

tcpdump -XX -i wlan0 port 80