January 2017 – Mohammed Wasay

A chart describing CIDR subnets

January 5, 2017January 5, 2017

Admins need to understand some basic networking concepts like CIDR. These are needed when working with AntiSpam & Archiving providers. Here is a simple chart describing the CIDR subnets.

32 = X-network-bits + Y-host-bits
Addresses = 2 ^ Y-host-bits
--------------------------------------------------------------
CIDR        Total number    Network             Description:
Notation:   of addresses:   Mask:
--------------------------------------------------------------
/0          4,294,967,296   0.0.0.0             Every Address
/1          2,147,483,648   128.0.0.0           128 /8 nets
/2          1,073,741,824   192.0.0.0           64 /8 nets
/3          536,870,912     224.0.0.0           32 /8 nets
/4          268,435,456     240.0.0.0           16 /8 nets
/5          134,217,728     248.0.0.0           8 /8 nets
/6          67,108,864      252.0.0.0           4 /8 nets
/7          33,554,432      254.0.0.0           2 /8 nets
/8          16,777,214      255.0.0.0           1 /8 net
--------------------------------------------------------------
/9          8,388,608       255.128.0.0         128 /16 nets
/10         4,194,304       255.192.0.0         64 /16 nets
/11         2,097,152       255.224.0.0         32 /16 nets
/12         1,048,576       255.240.0.0         16 /16 nets
/13         524,288         255.248.0.0         8 /16 nets
/14         262,144         255.252.0.0         4 /16 nets
/15         131.072         255.254.0.0         2 /16 nets
/16         65,536          255.255.0.0         1 /16
--------------------------------------------------------------
/17         32,768          255.255.128.0       128 /24 nets
/18         16,384          255.255.192.0       64 /24 nets
/19         8,192           255.255.224.0       32 /24 nets
/20         4,096           255.255.240.0       16 /24 nets
/21         2,048           255.255.248.0       8 /24 nets
/22         1,024           255.255.252.0       4 /24 nets
/23         512             255.255.254.0       2 /24 nets
/24         256             255.255.255.0       1 /24
--------------------------------------------------------------
/25         128             255.255.255.128     Half of a /24
/26         64              255.255.255.192     Fourth of a /24
/27         32              255.255.255.224     Eighth of a /24
/28         16              255.255.255.240     1/16th of a /24
/29         8               255.255.255.248     5 Usable addresses
/30         4               255.255.255.252     1 Usable address
/31         2               255.255.255.254     Unusable
/32         1               255.255.255.255     Single host
--------------------------------------------------------------

32 = X-network-bits + Y-host-bits

Addresses = 2 ^ Y-host-bits

--------------------------------------------------------------

CIDR Total number Network Description:

Notation: of addresses: Mask:

--------------------------------------------------------------

/0 4,294,967,296 0.0.0.0 Every Address

/1 2,147,483,648 128.0.0.0 128 /8 nets

/2 1,073,741,824 192.0.0.0 64 /8 nets

/3 536,870,912 224.0.0.0 32 /8 nets

/4 268,435,456 240.0.0.0 16 /8 nets

/5 134,217,728 248.0.0.0 8 /8 nets

/6 67,108,864 252.0.0.0 4 /8 nets

/7 33,554,432 254.0.0.0 2 /8 nets

/8 16,777,214 255.0.0.0 1 /8 net

--------------------------------------------------------------

/9 8,388,608 255.128.0.0 128 /16 nets

/10 4,194,304 255.192.0.0 64 /16 nets

/11 2,097,152 255.224.0.0 32 /16 nets

/12 1,048,576 255.240.0.0 16 /16 nets

/13 524,288 255.248.0.0 8 /16 nets

/14 262,144 255.252.0.0 4 /16 nets

/15 131.072 255.254.0.0 2 /16 nets

/16 65,536 255.255.0.0 1 /16

--------------------------------------------------------------

/17 32,768 255.255.128.0 128 /24 nets

/18 16,384 255.255.192.0 64 /24 nets

/19 8,192 255.255.224.0 32 /24 nets

/20 4,096 255.255.240.0 16 /24 nets

/21 2,048 255.255.248.0 8 /24 nets

/22 1,024 255.255.252.0 4 /24 nets

/23 512 255.255.254.0 2 /24 nets

/24 256 255.255.255.0 1 /24

--------------------------------------------------------------

/25 128 255.255.255.128 Half of a /24

/26 64 255.255.255.192 Fourth of a /24

/27 32 255.255.255.224 Eighth of a /24

/28 16 255.255.255.240 1/16th of a /24

/29 8 255.255.255.248 5 Usable addresses

/30 4 255.255.255.252 1 Usable address

/31 2 255.255.255.254 Unusable

/32 1 255.255.255.255 Single host

--------------------------------------------------------------

In networks larger than a /31, one address is used for the network number, another for the broadcast address, and generally another as the default…

Delete Files and Folders Older Than X Days

January 4, 2017January 4, 2017

Often times admin have to creates tasks like removing log files or some other files on a regular schedule. Here is an automated way of removing files / folders older than X days. Create a Batch file or Powershell script and add it to scheduled task. Batch File:

@echo off
:: set folder path
set dump_path=c:\shares\dump

:: set min age of files and folders to delete
set max_days=7

:: remove files from %dump_path%
forfiles -p %dump_path% -m *.* -d -%max_days% -c "cmd  /c del /q @path"

:: remove sub directories from %dump_path%
forfiles -p %dump_path% -d -%max_days% -c "cmd /c IF @isdir == TRUE rd /S /Q @path"

@echo off

:: set folder path

set dump_path=c:\shares\dump

:: set min age of files and folders to delete

set max_days=7

:: remove files from %dump_path%

forfiles -p %dump_path% -m *.* -d -%max_days% -c "cmd /c del /q @path"

:: remove sub directories from %dump_path%

forfiles -p %dump_path% -d -%max_days% -c "cmd /c IF @isdir == TRUE rd /S /Q @path"

Powershell:

# set folder path
$dump_path = "C:\shares\dump"

# set min age of files
$max_days = "-7"
 
# get the current date
$curr_date = Get-Date

# determine how far back we go based on current date
$del_date = $curr_date.AddDays($max_days)

# delete the files
Get-ChildItem $dump_path -Recurse | Where-Object { $_.LastWriteTime -lt $del_date } | Remove-Item

# set folder path

$dump_path = "C:\shares\dump"

# set min age of files

$max_days = "-7"

# get the current date

$curr_date = Get-Date

# determine how far back we go based on current date

$del_date = $curr_date.AddDays($max_days)

# delete the files

Get-ChildItem $dump_path -Recurse | Where-Object { $_.LastWriteTime -lt $del_date } | Remove-Item

Set password never to expire for users in a particular domain (Bulk mode)

January 3, 2017January 3, 2017

Let me start by saying that I don’t recommend doing this at all. Password Never Expires is bad security practice, but there are situations that might require it. I had a similar request on how this could be done. Setting it for multiple users:

#Connect of Office365
Import-Module MSOnline
$O365Cred = Get-Credential
$O365Session = New-PSSession â€“ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell -Credential $O365Cred -Authentication Basic -AllowRedirection
Import-PSSession $O365Session
Connect-MsolService â€“Credential $O365Cred 

#Get a List of user that belong to the second domain
$SDusers = Get-MsolUser -All -DomainName "yourseconddomain.com"

#Setting the password never to expire
ForEach($SDuser in $SDusers)
{
    Set-MsolUser -UserPrincipalName $SDuser -PasswordNeverExpires $true
}

#Connect of Office365

Import-Module MSOnline

$O365Cred = Get-Credential

$O365Session = New-PSSession â€“ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell -Credential $O365Cred -Authentication Basic -AllowRedirection

Import-PSSession $O365Session

Connect-MsolService â€“Credential $O365Cred

#Get a List of user that belong to the second domain

$SDusers = Get-MsolUser -All -DomainName "yourseconddomain.com"

#Setting the password never to expire

ForEach($SDuser in $SDusers)

{

Set-MsolUser -UserPrincipalName $SDuser -PasswordNeverExpires $true

}

Setting it for a single user:

Get-MSOLUser -UserPrincipalName user@domain.com | Select PasswordNeverExpires

1	Get-MSOLUser -UserPrincipalName user@domain.com \| Select PasswordNeverExpires

Get PasswordAge for users in a particular domain

January 3, 2017

In Office365 if you have more than one domain in a subscription, there are times where you may want to get the password age for users of that domain. In my case to check which users are covered and meeting policy and get the users addressed.

Get-MsolUser -All -DomainName "yourdomainname.com" | select DisplayName, LastPasswordChangeTimeStamp,@{Name=â€PasswordAgeâ€;Expression={(Get-Date)-$_.LastPasswordChangeTimeStamp}}

1	Get-MsolUser -All -DomainName "yourdomainname.com" \| select DisplayName, LastPasswordChangeTimeStamp,@{Name=â€PasswordAgeâ€;Expression={(Get-Date)-$_.LastPasswordChangeTimeStamp}}

The output will be similar to: