Jemson's Blog

Teams PowerShell Reference Commands

Wed, 09 Mar 2022 00:00:00 +1100

Had to provide a customer with Teams PowerShell reference commands, so though why not post it here for later use. These make up some of the most common commands in User setup and management.

#Install Teams Modules in PowerShell (Only needs to be done once)
Install-Module -Name MicrosoftTeams

# Connect in PowerShell (Need to do each time you run powershell)
Connect-MicrosoftTeams
# This will then prompt for admin credentials to connect

# Enable User and Assign Phone Number / Voicemail
Set-CsUser -Identity "user@email.com" -LineURI tel:61234567890 -EnterpriseVoiceEnabled $true -HostedVoiceMail $true

# Set Routing Policy
Grant-CsOnlineVoiceRoutingPolicy -Identity "user@email.com" -PolicyName "AU-CentralEast-International"

# Set Dial Plan
Grant-CsTenantDialPlan -Identity "user@email.com" -PolicyName "AU-NSW"

# Get a list of enabled Users
Get-CSOnlineUser | Where { $_.EnterpriseVoiceEnabled } | Select-Object UserPrincipalName,DisplayName,LineURI

# Export a list of enabled Users and export to UserData.csv (For filtering in Excel for free numbers etc)
Get-CSOnlineUser | Where { $_.EnterpriseVoiceEnabled } | Select-Object UserPrincipalName,DisplayName,LineURI | Export-Csv -Path UserData.csv

Docker and iptables

Mon, 07 Mar 2022 00:00:00 +1100

Something that came to bite me this week, was Docker’s ability to insert it’s own iptables rules completely bypassing firewall-cmd / ufw.

On this particular server I had LAN/WAN interfaces directly assigned the the firewall policy configured in such a way that would allow HTTP/HTTPS traffic in on the public interface, but internally would accept connections on 8080/8081 for some other internal services. Not on Docker’s watch!!

Docker added it’s own iptables rules around it’s bridge interface that meant it would also pass connections on 8080/8081 on the WAN side! For mitigating this, (from Docker 20.10) there is apparently an --iptables=false attribute that can be passed to docker init to stop this behaviour, though I read mixed feedback on this potentially causing other container issues.

For mine, I resolved by adding the specific listner IP into the docker port binding. Eg: docker run -d -p 192.168.1.10:8080:8080 to only listen on the internal side, which caused it to monitor it’s iptables rules accordingly. One take away from this; Be specific.

Interactive Learning

Fri, 11 Feb 2022 00:00:00 +1100

Have come across a really fun interactive learning site called Try Hack Me.

While not exactly new, (and just shy on 1 Million users at the time of writing) it is something I have only recently just found out about. After signing up a free account, and having a play for a couple of hours, I found it very immersive and educational and fronted up the money for a paid subscription!

Hopefully over the coming months I will provide some blog entries about little nuggets I pick up here as I get time!

Django ALLOWED_HOSTS Limitation

Tue, 18 Jan 2022 00:00:00 +1100

Ran into an issue today that took quite a long time to get to the bottom of. That issue was that the ALLOWED_HOSTS parameter in Django doesn’t accept records containing and underscore (_).

After some further reading found that the reason behind this is that _ isn’t a valid character in domain names, so is excluded from being used in ALLOWED_HOSTS. In my case it was being used as part of a docker container name, so that nginx could source the django container by name/alias easily.

Apparently you can modify the regex usage in Django to get around this, but that seemed like a bit of a cludge method to me, so I renamed the containers to use hyphen (-) instead of underscore (_).

Figured this was worthy of note :)

Linux SSH Port Forwarding

Fri, 14 Jan 2022 00:00:00 +1100

Until now I have been blessed with the ease of the PuTTY UI in Windows to do SSH port forwarding, so today had to look up how to do the forward from a linux terminal.

Turns out it is super easy. ssh -p<SSH-PORT> <SSH-HOST> -L <LPORT>:<RHOST>:<RPORT>

Eg, To forward 8443 locally to 443 on 192.168.1.10: ssh -p2200 11.22.33.44 -L 8443:192.168.1.10:443

Installing DotNet 3.5 Without DVD

Thu, 13 Jan 2022 00:00:00 +1100

This has stumped me a number of times and I have tried all sorts of things to get around the issue of installing dotNet 3.5 on Windows Server without having to mount the DVD.

Finally today I found this post showing how to change local group policy to force the server to download the package from Windows Update.

In short;

Start the Local Group Policy Editor or Group Policy Management Console (WIN+R and type gpedit.msc).
Expand Computer Configuration Folder–> then click expand Administrative Templates Folder–> then select System.
Double click to open Specify settings for optional component installation and component repair Group Policy setting, and then select click Enabled.
Also click Enable for Contact Windows Update directly to download repair content instead of Windows Server Update Services (WSUS) checkbox.

Now go to Add Roles and Features Wizard and select enabling checkbox .NET Framework 3.5 and get it installed successfully.

Welcome to the Internet

Wed, 12 Jan 2022 00:00:00 +1100

2022, the year the blog returned!

It’s been about 10 years since the last blog was lost forever, however many lessons have been learned this time around.

Have decided to use Jekyll to publish instead of relying on any database, which also makes backing up or moving the site a breeze (It was also really easy to set up!).

Decided to go this route after listening to a talk by Jack Rhysider from Darknet Diaries about blogging. Great podcast if you haven’t listened to it!

I quite like this theme, but haven’t explored too many, so it may change but will see how it fares.