Exchange SMTP Internet Connector frequently down

Description:
You have Exchange 2003 Front-End server configure to route emails to third party appliance smart host. One day the Exchange Internet connector frequently converted to down state causing mail queue when sending to external address. No issue when the connector is configures to use DNS instead of smart host to dispatch email. You have check for possible Antivirus or SMTP Protocol issue using Winroute and Regtrace but everything looks ok.
On the Netmon trace result, you can see that Exchange didn’t receive ACK for certain packet from the smart host and it terminates the connection after some times.

Resolution:
Make sure that the network speed and duplex setting at the smart host is the same with the connection setting at core switch. Running manual setup might be required to eliminate the issue.

Missing PTR Record in DNS

Description

You create a PTR record on your Active Directory Integrated DNS Server. After a while the PTR record suddenly missing. Your Active Directory and your DNS server are working fine. Replication between Domain Controller also working normally.

Resolution

Be sure the "register this connection's addresses to the DNS" checkbox option is enable, the server than will automatically register its ptr record to the DNS server.

Enable Strict Replication Consistency

Description
Supposed a domain controller get disconnected from the replication topology for an extended period and then later on reconnect it. You need to make sure that no outdated Active Directory objects can be replicated within the forest.

Resolution
Use regedit command and go to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NTDS\Parameters
Create a Strict Replication Consistency with REG_DWORD data type. Set 1 as the value.

This setting ensures that no outdated objects are reintroduced into Active Directory Domain Services (AD DS).
You need to set it on all of the Domain Controller within the Forest.

Error when burning CD

Have you ever get an issue when trying to burn some files to a CD/DVD?
In my case I got error writing Lead-In when trying to burn some file using UltraISO on my IBM T42 CD ROM (HL-DT-ST RW/DVD GCC-4242N). I can use it to read any CD/DVD with no issue.
I try to change the burner software to Nero but got similar error too. Try to lower the burning speed with no luck.
Previously I remember that I can burn a CD with that CD ROM, somehow it's just stop working.
I try to search for a driver update but cannot find any. A firmware update maybe available but I think that's too much for the issue.
Finally I try to clean the lenses. Just wipe it with a clean tissue, try to burn, and it works.

AD Modify

If you ever need to change an attribute for a lot of user in Active Directory, you might want to use ADModify.Net tools. It is available free.

Following is the example for querying any user that has empty mobile phone number field in Active Directory.

(&(&(objectcategory=person)(objectclass=user))(!mobile=*))