The following reply was made to PR kern/29126; it has been noted by GNATS.

From: kim@tac.nyc.ny.us (Kimmo Suominen)
To: gnats-bugs@netbsd.org
Cc: 
Subject: Re: bin/29126: tcpdump leads to packet loss
Date: Thu, 27 Jan 2005 11:05:26 -0500 (EST)

 I see the loss of traffic also happening on tlp and gsip and using dumb
 switches (i.e. no STP in use).
 
 It definitely was not happening with earlier versions of NetBSD.
 
 The only "old" version I have around anymore is 1.6B.  The NIC's I have
 on that are fxp and tlp.  Neither one exhibits this problem.
 
 How to test:  start tcpdump on the interface you are connected over,
 and hit RETURN repeatedly to verify if tty echoes it back immediately.
 
     inet-fw:~# tcpdump -i tlp0 port 22
     tcpdump: listening on tlp0
 
 
 
     17:59:57.387560 inet-fw.xxx.xxx.ssh > beowulf.gw.com.63960: [...]
 
 The empty lines above are the tty driver echoing my RETURN keypresses.
 
 With 2.99.x there is no echoback until the network resumes functioning.
 
 If this is a NIC driver issue, then it would need to be an change made
 to at least ex, gsip and tlp, since I don't recall the problem with any
 of them with earlier versions.
 
 I hope this helps.
 
 Regards,
 + Kim