Network Stumbler

Cam told me about a great simple utility for surveying wireless networks: http://www.netstumbler.com/

Microsoft .NET Framework 3.0 Error Code: 0x643

In setting up 2 new XP installations, I was getting a failed Windows Update on .NET 3.0. The fix ended up being to install .NET 3.0 manually from:
http://www.microsoft.com/downloads/details.aspx?FamilyId=10CC340B-F857-4A14-83F5-25634C3BF043&displaylang=en

Can't Remote Desktop

There are many reasons why you can't remote desktop to a PC, but if you notice that you can remote desktop to a computer from location A, but NOT location B, then check your Windows firewall group policy for your remote desktop policy. You can restrict which subnets will accept remote desktop messages from at Computer Configuration | Administrative Templates | Network/Network Connections/Windows Firewall/Domain Profile.

Stale DHCP Reservation

When I tried to PXE boot a test PC, I couldn't get a DHCP address because there this PCs MAC had a duplicate DHCP reservation. The error I got was "ProxyDHCP service did not reply to request on port 4011". Removing the DHCP reservation for this MAC solved the problem. Thankfully, Windows 2003 Server DHCP labelled the reservation BAD_ADDRESS for me.

SMTP Delay

Users were getting a 30 second delay in starting their SMTP connection to our Plesk qmail service due to an rDNS lookup . To eliminate this delay, I followed a suggestion from a Plesk forum, added the -R switch to NOT obtain TCPREMOTEINFO from the remote host (refer to the tcp-env manpage) . I also had to remove the relay check to relays.ordb.org (removed -r relays.ordb.org ).

In summary, in /etc/xinetd.d/smtp_psa, I changed
server_args = /usr/sbin/rblsmtpd -r relays.ordb.org ...
to
server_args = -R /usr/sbin/rblsmtpd /var/qmail/bin/relaylock ...

Bad Yahoo Toolbar, Bad!

A user was getting an application error when quitting from IE7. I ended up fixing the problem by disabling Yahoo! toolbar. I've also subsequently uninstalled it as well.

The error appears in event viewer | application as:

Event Type: Error
Event Source: Application Error
Event Category: None
Event ID: 1000
Date: 1/8/2007
Time: 11:12:45 AM
User: N/A
Computer:
Description:
Faulting application iexplore.exe, version 7.0.5730.11, faulting module ntdll.dll, version 5.1.2600.2180, fault address 0x00001010.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 41 70 70 6c 69 63 61 74 Applicat
0008: 69 6f 6e 20 46 61 69 6c ion Fail
0010: 75 72 65 20 20 69 65 78 ure iex
0018: 70 6c 6f 72 65 2e 65 78 plore.ex
0020: 65 20 37 2e 30 2e 35 37 e 7.0.57
0028: 33 30 2e 31 31 20 69 6e 30.11 in
0030: 20 6e 74 64 6c 6c 2e 64 ntdll.d
0038: 6c 6c 20 35 2e 31 2e 32 ll 5.1.2
0040: 36 30 30 2e 32 31 38 30 600.2180
0048: 20 61 74 20 6f 66 66 73 at offs
0050: 65 74 20 30 30 30 30 31 et 00001
0058: 30 31 30 0d 0a 010..