Windows DHCP Logs

Summary

Windows 2000/2003 DHCP server only retains log files for seven days in the following location c:\windows\system32\dhcp\ in the following formats:

DhcpSrvLog-Mon.log
DhcpSrvLog-Tue.log
DhcpSrvLog-Wed.log
DhcpSrvLog-Thu.log
DhcpSrvLog-Fri.log
DhcpSrvLog-Sat.log
DhcpSrvLog-Sun.log

After which they are overwritten

Symptoms

Logfiles are needed to be retained for a longer period

Cause

This is the default windows 2000/2003 behaviour, although log file sizes can be modified, the retention period cannot

Question

How can I automatically back these logs up prior to them being overwritten and append each log file with the date

Answer

Create the following vbscript and schedule it to run on the Windows Server.

Const OverwriteExisting = TRUE
Set objFSO = CreateObject("Scripting.FileSystemObject")
objFSO.CopyFile "C:\windows\system32\dhcp\DhcpSrvLog-Mon.log" , "C:\dhcp_logs\", OverwriteExisting
objFSO.CopyFile "C:\windows\system32\dhcp\DhcpSrvLog-Tue.log" , "C:\dhcp_logs\", OverwriteExisting
objFSO.CopyFile "C:\windows\system32\dhcp\DhcpSrvLog-Wed.log" , "C:\dhcp_logs\", OverwriteExisting
objFSO.CopyFile "C:\windows\system32\dhcp\DhcpSrvLog-Thu.log" , "C:\dhcp_logs\", OverwriteExisting
objFSO.CopyFile "C:\windows\system32\dhcp\DhcpSrvLog-Fri.log" , "C:\dhcp_logs\", OverwriteExisting
objFSO.CopyFile "C:\windows\system32\dhcp\DhcpSrvLog-Sat.log" , "C:\dhcp_logs\", OverwriteExisting
objFSO.CopyFile "C:\windows\system32\dhcp\DhcpSrvLog-Sun.log" , "C:\dhcp_logs\", OverwriteExisting

Dim wFile
With CreateObject("scripting.filesystemobject")
Set wFile = .GetFile("C:\dhcp_logs\DhcpSrvLog-Mon.log")
wFile.Name = "DhcpSrvLog-Mon_" & Replace(Date, "/", "-") & ".log"
Set wFile = .GetFile("C:\dhcp_logs\DhcpSrvLog-Tue.log")
wFile.Name = "DhcpSrvLog-Tue_" & Replace(Date, "/", "-") & ".log"
Set wFile = .GetFile("C:\dhcp_logs\DhcpSrvLog-Wed.log")
wFile.Name = "DhcpSrvLog-Wed_" & Replace(Date, "/", "-") & ".log"
Set wFile = .GetFile("C:\dhcp_logs\DhcpSrvLog-Thu.log")
wFile.Name = "DhcpSrvLog-Thu_" & Replace(Date, "/", "-") & ".log"
Set wFile = .GetFile("C:\dhcp_logs\DhcpSrvLog-Fri.log")
wFile.Name = "DhcpSrvLog-Fri_" & Replace(Date, "/", "-") & ".log"
Set wFile = .GetFile("C:\dhcp_logs\DhcpSrvLog-Sat.log")
wFile.Name = "DhcpSrvLog-Sat_" & Replace(Date, "/", "-") & ".log"
Set wFile = .GetFile("C:\dhcp_logs\DhcpSrvLog-Sun.log")
wFile.Name = "DhcpSrvLog-Sun_" & Replace(Date, "/", "-") & ".log"
End With

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Document ID: SKB0458
Published on: 30 Nov 2006