Flush ARP cache

To flush/Delete the ARP cache in Windows 2000/2003, run the following command;
netsh interface ip delete arpcache

Delete IP address using arp command
arp -d <ip address>

Display arp table
arp -a

Add static entry to ARP table
arp -s <ip address> <mac address>

Locating the MAC address of a networked computer from Windows:

Locating the MAC address of a networked computer from Windows:

1. Click Start -> Run, type cmd and click Ok
2. Type ping <ipaddress>
3. After the ping response has finished, type arp -a
4. Under Internet Address, locate the IP address you just pinged. In the same line, the corresponding MAC address is listed under Physical Address

VMware Accident

I did the following by accident:

I created a new vmkernel port for vMotion. When I created this port the default gateway was changed to the new vmkernel port. This prevented the management interface being reached as the default gateway was now pointing to the vmkernel port on vSwitch1.

So to fix:

Check the status of the NICs on the ESX host.

   # esxcfg-nics -l

This showed that the NIC 'vmnic0' was active and 'vmnic1' was in a down state.

Checked the vSwitch configuration with the following

   # esxcfg-vswitch -l

This confirmed a new vmkernel port 'vmk1' was created in a portgroup 'VMkernel' on 'vSwitch1'.

As this was the new vSwitch that I'd created, I removed it as it was working before the change.

   # esxcfg-vmknic -d "VMkernel"

   # esxcfg-vswitch -d vSwitch1

However, this didn't resolve the issue.

Tried to ping the default gateway

   # vmkping x.x.x.x

This worked fine.

Then tried a diagnostic ping

   # vmkping -D

This reported the default gateway wasn't set.

This was corrected by:

   # esxcfg-route x.x.x.x

This resolved the issue and restored access to the ESX host.

Problem with Windows Task Scheduler

http://social.technet.microsoft.com/Forums/en-US/winservermanager/thread/d47d116e-10b9-44f0-9a30-7406c86c2fbe/

RDP problem

Different versions of RDP can cause problems. If it won't connect and you're sure you've done all the usual stuff, try:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\TermService\Parameters
Under this registry subkey, delete the following values
• Certificate
• X509 Certificate
• X509 Certificate ID