Ethereal-users: Re: [Ethereal-users] Query regarding ethereal 0.9.2

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 This list is no longer active.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: Tue, 5 Mar 2002 13:07:24 -0800
On Tue, Mar 05, 2002 at 08:22:45AM -0500, Simi A R wrote:
> This is GNU ethereal 0.9.2, compiled with GTK+ 1.2.8, with GLib 1.2.8,
> with libpcap 0.6, with libz 1.1.3, without SNMP
>                               ^^^^^^^^^^^^
> ethereal [ -vh ] [ -klpQS ] [ -a <capture autostop condition> ] ...
>         [ -b <number of ringbuffer files> ] [ -B <byte view height> ]
>         [ -c <count> ] [ -f <capture filter> ] [ -i <interface> ]
>         [ -m <medium font> ] [ -n ] [ -N <resolving> ]
>         [ -o <preference setting> ] ... [ -P <packet list height> ]
>         [ -r <infile> ] [ -R <read filter> ] [ -s <snaplen> ] 
>         [ -t <time stamp format> ] [ -T <tree view height> ]
>         [ -w <savefile> ] [ <infile> ]
> 
> But the News for Ethereal 0.9.2 on www.ethereal.com says this version
> supports SNMP.

Well:

	1) "without SNMP" means "not linked with an SNMP library to
	   read MIB files and use that information to report OIDs
	   symbolically and print variable bindings as per what the MIB
	   says", not "without support for SNMP at all";

	2) if you have an SNMP library, you have to explicitly say
	   "--enable-snmp" to get it linked in, because there are some
	   buffer overflow vulnerabilities in the SNMP library code, as
	   well as some in Ethereal, that show up only when linked with
	   the SNMP library code, and they're not yet fixed as of 0.9.2,
	   so we temporarily made "link without the SNMP library" the
	   default.

> I tried enabling "SNMP" using the Edit -> Protocols Option of the GUI.

Umm, it's enabled by default - *all* protocols are enabled by default -
so, if you clicked on the "snmp" button, you probably *disabled* SNMP.

> Even then, the tool is not capturing SNMP data.
> Instead it is showing it as the data part (in hex format) of UDP packet. 

You mean it's not *dissecting* SNMP data.  It *is* capturing the data,
as you are seeing the UDP packets; it's just not dissecting it as SNMP.

If, as I suspect is the case, you disabled SNMP dissection, then it
*won't* dissect anything as SNMP.  Try starting Ethereal again,
*without* doing anything with SNMP in the "Edit->Protocols" option, and
see what happens.