IE6SP1 first browser connection fails (any site).

Hi,

we have 2 Small Business Suite 5.1sp4 server(s) running BM3.5sp3 & C11
patches plus others installed.

On W2KSP3 workstations, if we run IE6.0 (no SP1) then things work OK. If
we apply IE6SP1 then the first connection through the proxy fails. Even
when we apply all current patches (not W2KSP4), the first connection
still fails, hit return second connection always makes, and any other
connections in that browser session.

XP Pro works fine with IE6SP1 and/or XPSP2 applied. We are using client
trust to authenticate to proxy.

We would like to patch these servers further but some bright spark at
Novell told us we could run Legato standby server in this setup. After
initial problems with SBS we stabilised the system, only to be told by
Leagato this is not a supported config. As the SBS is working fine we
don't want to upset things by patching servers if we can help it.
Upgrade to NW6.5 is happening in new year. Any ideas on the IE6 (until
we upgrade) as we have a number of critical production applications that
will not install without IE6SP1.

TIA.