Tuesday, November 21, 2006



Yet another great utility built-in to Windows that I just learned about.


It's like tracert on steroids.

Of course it helps when you have a need for it: I'm trying to troubleshoot latency issues that users in India are having connecting to a Citrix farm in Columbia, MD. I just mapped the full link today and found 17 logical hops between workstation and server, with at least 21 physical hops (and there are most likely more physical links than that). The average 280ms latency is understandable and would be functional if it were consistent. It's the regular latency spikes from 3000-9000ms that last for 15-90 seconds that I think is a problem. :(

Wednesday, November 08, 2006


Searching DHCP

We all know the DHCP console sucks for searching. The columns don't sort accurately and it's hard to find a specific system, especially in a large scope. Netsh to the rescue!

Find a reservation

netsh -r servername dhcp server scope scopeaddress dump | find /i "searchvalue"
where servername is the name or IP address of the DHCP server on which the scope is defined, scopeaddress is the IP address of the scope in question, and searchvalue is the client IP address, MAC address (undelimited), computer name or text description (/i ignores case).

netsh -r dhcpsvr1 dhcp server scope dump | find /i "aaron-laptop"
dhcp Server Scope Add reservedip 01234567890a "aaron-laptop." "Aaron Czechowski" "BOTH"

Find a lease

netsh -r servername dhcp server scope scopeaddress show clients | find /i "searchvalue"
searchvalue options: IP address, MAC address (hyphen delimted).

netsh -r dhcpsvr1 dhcp server scope show clients | find /i "01-23-45-67-89-0a" - 01-23-45-67-89-0a -11/11/2006 8:05:23 PM -D

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