using tcpdump with wifi-tether causes packets to output(dump) AND then mysteriously disappear before being sent over internet

[GoogleCodeExporter]

Which device (manufacturer, type)?
Droid X

Which firmware is installed?
2.2.1 Stock (Kernel 2.6.32-9)

What version of wireless tether are you using?
2.0.6

What steps will reproduce the problem?

Pre: Obtain a copy of tcpdump OR use an app like 'Shark' from the market which 
already has tcpdump included

1. Start wifi-tether (Unsecure or secured AP - same results)
2. Use a wifi device (laptop) to connect then open webpage or do an ICMP ping 
(notice that they work) to some internet address
3. Run tcpdump OR push start on 'Shark'
4. Try the same webpage or try an ICMP ping (note that both don't work this 
time)
5. Look at the tcpdump output: You can see that the packets were found (eg: TCP 
SYN requests or ICMP) - but they never made it to the internet

What is the expected output? What do you see instead?
tcpdump should transparently dump traffic without causing it to mysteriously 
disappear after being dumped(output)

Please provide any additional information below.
1) Traffic that originates on the phone itself is unaffected and still works - 
Only wifi clients are affected
2) If you do a tcpdump on the remote computers you can see that they *never* 
get any packets when tcpdump is running on the phone. As soon as you kill 
tcpdump the packets start arriving again
3) If you tcpdump on tiwlan0 or ppp0 you always get the same effect for both 
cases: Packets disappear after being dumped. There appears to be no difference
4) If you selectively only tcpdump for port 80 then only http traffic 
disappears - anything other than port 80 keeps working. This applies for any 
filter of course, not just port 80.

Original issue reported on code.google.com by davidfi...@gmail.com on 20 Jan 2011 at 9:10

[GoogleCodeExporter]

This issue doesn't affect incoming packets.
Eg:
tcpdump 'src remoteIP'
will successfully dump RECEIVED packets and pass them on to the wifi client.

However:
tcpdump 'dst remoteIP'
will dump transmitted packets, but then they disappear (never making it to 
destination on the internet)

Original comment by davidfi...@gmail.com on 20 Jan 2011 at 9:23

[GoogleCodeExporter]

When tested on an HTC Evo 4G with Cyanogen 6.1.2 this problem does NOT occur. 
Haven't tested this with a stock Evo ROM yet.

Original comment by davidfi...@gmail.com on 20 Jan 2011 at 10:39