Multicast – IGMP Snooping and IGMP Querier – Sender and Reciever(s) in same VLAN/Layer 2 Segment

Multicast is a networking method used to efficiently transmit data to multiple recipients simultaneously. Unlike unicast (one-to-one) and broadcast (one-to-all) communication, multicast is a one-to-many or many-to-many method where data is sent only to devices that are interested in receiving it, rather than to all devices on a network. In multicast, devices that want to […]

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VMware PowerCLI Discover VMs Restarted by VMware HA (Host Failure)

VMware HA (High Availability) is a great feature, but if the failure occurs when you are not watching it you may well need to know what was affected. You can use VMware PowerCLI to query vCenter for the VMs that have been affected by a host failure causing an HA restart event. I’m assuming that […]

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AWS Transit Gateway with VPN to On-Premise Palo Alto Firewall

The AWS Transit Gateway can be used to join the networking of many VPCs (in the same or different AWS Accounts) within the same region together to facilitate communication, it may also be used in conjunction with DX (Direct Connect) or Site-to-Site VPNs to provide connectivity to other Cloud Platforms but additionally to on-premise networks […]

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VMware vCenter – “Exception in invoking authentication handler User password expired”

An appliance that was deployed over 90 days old with no changes made to the default settings. When attempting to logon to the VAMI console of the appliance i.e. https://vcenter.domain.com:5480 you get the message: “Exception in invoking authentication handler User password expired”. To resolve this you need to reset the password, then set it not […]

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Active Directory Read Only Domain Controller (RODC) – “there are currently no logon servers available to service the logon request”

We had an issue where our RODCs suddenly stopped authenticating users and also would not allow administrators to logon via RDP or locally via the console giving this message: “there are currently no logon servers available to service the logon request” Any downstream services that were trying to authenticate via LDAP or LDAPS also failed […]

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Query Message Tracking Logs on Microsoft Exchange using Powershell

You want to search your Microsoft Exchange message tracking logs to track an email, you can do this using a Powershell command (run from the Microsoft Exchange Powershell console), the below command will query all your Microsoft Exchange servers to find the tracking logs and then obtain all emails sent by the user “sender@domain.com” between […]

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