Unable to Remove Host from vSphere Distributed Switch (The resource ‘105’ is in use)

We were performing the migration to new Distributed Switches (running a later version) ready for our vCenter 7.x and ESXi 7.x upgrade and when attempting to remove a host from a distributed switch we got this error: VMware has an article KB76959 that describes this issue, however in our case rather than the VM (or … Read more

Requirements Collection Thoughts

The collection of user requirements can be a difficult and time-consuming process, working towards Agile principles the collection of requirements should be a collaborative process helping the requestor (customer/colleague) to discover what they want through requirements collection sessions to build a document that contains the necessary information for the design teams to build a solution … Read more

URLs, URIs, URNs and their Structure

So in performing an emergency workaround for a zero-day on a Microsoft Exchange server, I came across a term: URI. It’s something I’ve met before, but then realised, what actually is a URI? So I set out to find out and like many things went down a rabbit hole! In this article I’ll try to … Read more

Exchange 2016 – Security Update For Exchange Server 2016 CU22 (KB5015322) – OWA Failed After Update

After an update Microsoft Exchange 2016 – Security Update For Exchange Server 2016 CU22 (KB5015322), following the upgrade the following appeared: The Exchange server appeared to operating fine, mail flow was fine, the DAG operating as expected, users who are using ActiveSync, Exchange Anywhere or EWS all appeared to have no problems. However using OWA … Read more

Extreme Networks VOSS Switch – SNMP(v3) Configuration and Monitoring Configuration

Moniting with SNMPv3 is much like monitoring with SNMPv2 or 1 for that matter, except SNMPv3 offers greater security options. SNMPv1 or v2 offers very little security being based on a plain text community string, of course on the monitored device you can restrict which hosts are allowed to connect to your monitored device via … Read more

NMAP Port Scanning States

NMAP (Network Mapper) is a great tool for scanning your network to identify active hosts and the open/available services they have. NMAP provides quite a granular output for the port states, six in-fact, rather than just an open and closed. I’ll give a brief overview of the three main ones you’ll come across: Open, Closed … Read more

Testing iSCSI Connectivity from VMware ESXi to Storage

If you wish to test the connectivity through from your VMware ESXi host through to its storage when using iSCSI you can perform steps such as the following described within: https://kb.vmware.com/s/article/1003728 Firstly run this to get your list of vmKernel ports: Assuming you’ve labelled the vmKernel ports you use for iSCSI with something sensible you … Read more

VMware Distributed Virtual Switch Version Upgrade via Side-by-Side Migration (vSwitch 6.0.0 to 6.5.0 or 6.6.0)

VMware have recommended that upgrading from Distributed vSwitch version: 6.0.0 to 6.5.0 or 6.6.0 should be done as a side by side migration rather than an in place upgrade due to the risk of outage when performing the upgrade in place, this is detailed in the following VMware article: https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.networking.doc/GUID-330A0689-574A-4589-9462-14CA03F3F2F4.html. It is understood that vDS … Read more

Separation of Duties, Two-Person Control, (Principle of) Least Privilege and Need to Know

Information Security has a number of foundational concepts, such as the Confidentiality, Integrity and Availability of information, information assets and services. In this article we’ll explore four key concepts that are good to understand to assist you in building and configuring secure systems and therefore protecting and improving the Confidentiality, Integrity and Availability of your … Read more