More on using FreeTDS on a server (was Re: [freetds] Server dumpscore...)

James K. Lowden jklowden at
Thu Apr 22 22:22:21 EDT 2004

On Thu, 22 Apr 2004 18:57:37 -0700, "Mike C." <mcbp223 at> wrote:
> > From: James K. Lowden [mailto:jklowden at]
> > Sent: Thursday, April 22, 2004 3:48 PM
> > On Thu, 22 Apr 2004, "Mike C." <mcbp223 at> wrote:
> > > it sends TDS_PRELOGIN(0x12), to check if you're talking TDS7+; if
> > > you just send done (#253),
> >
> > That's a facinating bit of intelligence.  Have you decoded the 0xl2
> > packet?
> >
> The only attempt to describe the prelogin packet that I could find was
> an analysis for a security exploit, do a google for CNETLIBVER. They
> didn't analyze however what SQL Server sends back.

OK, thanks. If you happen to have a trace handy sometime, I'd like to have
a look.   

> > On my wishlist is to make TDSVER obsolete except for tuning.  Perhaps
> > we can start by sending a prelogin packet, fall back to 5.0, then fall
> > back to 4.2.  Seems completely doable and worthwhile.
> >
> I believe the prelogin dialog is valid only for MS, not for Sybase, so I
> don't think you can fall back to 5.0, but to 4.2 sure. Again this is
> what I suppose, I don't have access to any Sybase product to check it.

I suspect it might work.  Worth looking into at some point.  

If you need access to a Sybase server, I can arrange it.  


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