Hi all

Config:
- 2x W2k3 STD servers running IIS6.0 in NLB.

Need:
- The need has now arisen to run a script on one of the servers that
connects to itself and the other server by means of UNC, so started enabling
the services again and it has all gone pear-shaped.

Problem:
- I CAN access both servers using UNC from my pc
- I CAN access OTHER servers using UNC from the webservers
- However, when I connect to each of the servers from the other using UNC it
doesn't connect - I can't even ping it - but it does resolve.
- I've set all the services back to original, and even removed the group
policy but no go.
- What is strange is that it actually works for about 5 minutes if I
restart both servers - and then just falls over .. nothing being reported in
event viewer, etc at the time.
- I've already rebuilt these servers once!

Also, I've tried these solutions to no avail:
http://www.jsiinc.com/SUBR/tip8500/rh8517.htm
http://support.microsoft.com/?kbid=841570

Marlon

NLB obfuscates the physical MAC address of each node in the cluster by
default unless you take special steps to allow resolution of the physical
MAC address on each node through a method known as

The fact that node resolution worked for five minutes after server restarts
is because it is occurring before convergence completes. After cluster
convergence completes the switch doesn't know what to do when more than one
switched port claims to own the same MAC address.

http://support.microsoft.com/default.../WCT032102.asp

--
Todd J Heron, MCSE
Windows Server 2003/2000/NT
----------------------------------------------------------------------------
This posting is provided "as is" with no warranties and confers no rights

I don't seem to recall the same thing happening when I had a couple of
Windows 2000 servers running a while ago.

Anyways .. I found this article too:

http://www.microsoft.com/technet/pro...ing/nlbbp.mspx

and I quote:
General Considerations
. Some routers require a static ARP entry because they do not support
the resolution of unicast IP addresses to multicast media access control
addresses. For example, Cisco routers require an ARP (address resolution
protocol) entry for every virtual IP address. While Network Load Balancing
uses Level 2 Multicast for the delivery of packets, Cisco's interpretation
of the RFCs is that Multicast is for IP Multicast. So, when the router
doesn't see a Multicast IP address, it does not automatically create an ARP
entry, and one has to manually have to add it on the router.



. Network Load Balancing can operate in two modes: unicast and
multicast. Unicast support is enabled by default, which ensures that it
operates properly with all routers. You might elect to enable multicast mode
so that a second network adapter is not required for communications within
the cluster. If Network Load Balancing clients access a cluster (configured
for multicast mode) through a router, be sure that the router accepts an
Address Resolution Protocol (ARP) reply for the cluster's (unicast) IP
addresses with a multicast media access control address in the payload of
the ARP structure. ARP is a TCP/IP protocol that uses limited broadcast to
the local network to resolve a logically assigned IP address. Verify that
all cluster hosts are operating in unicast or multicast mode, one or the
other, but not both.



. If the cluster is operating in unicast mode (default setting),
Network Load Balancing cannot distinguish between single adapters on each
host. Therefore, any communication among cluster hosts is not possible
unless each cluster host has at least two network adapters.



Thanks Todd

Marlon




"Todd J Heron" <todd_heron_no_spam@hotmail.com> wrote in message
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