Ethereal-dev: Re: [ethereal-dev] Ethereal Win32 libpcap patch.

Note: This archive is from the project's previous web site, ethereal.com. This list is no longer active.

From: Guy Harris <guy@xxxxxxxxxx>
Date: Wed, 9 Feb 2000 11:41:44 -0800 (PST)
> That said, Ethereal-win32 with pcap won't work for me. I've installed
> the packet capture driver and WinDump works fine for me. However,
> when I try to start a capture with Ethereal-win32, I get:
> 
> Can't use filter: Couldn't obtain netmask info (Unknown host name).

I've had the same problem.

On UNIX, libpcap obtains the network mask for an interface by doing
"ioctl"s on a socket (the netmask is used when processing filter
expressions).

The Politecnico di Torino port gets it by attempting to get the host
name and, if that's successful, trying to look up the host name, getting
the IP address from that, and assuming that it's on a class A, B, or C
network.

My home machine has a name that's not registered in DNS (its "official"
name in DNS is some mess based on the IP address my ISP assigned it, but
my machine thinks its name is just "quadrajet"); this probably causes
that code to fail.

I've been working on a change to the Politecnico libpcap to dredge the
netmask information from the registry (which not only handles this case,
but better handles the case of a multi-homed host, and handles the case
of a host with a CIDR netmask); unfortunately

	1) I haven't yet figured out how to get WinDbg to show more
	   power than "adb";

	2) I haven't yet figured out how to use the Visual C++ 6.0
	   debugger without having the Borg assimilate the entire
	   project (no, I don't want to make a Visual Studio project out
	   of it, I still want to use the Nmakefiles);

	3) I've bumped into other problems trying to get that to work;

so I don't have it working yet.

I also don't have a Windows 9x machine (I guess I could try it inside
VMware, but so far my VMware experiences haven't been all that
wonderful, and I haven't yet figured out whether I have to give my
machine's Ethernet interface multiple IP addresses in order to make
networking work inside VMware or if the VMware interfaces handle that),
so I don't know what the way to do that on W9x is.