SSH Legacy Key Algorithms

Sometimes you have some kit that is just old and isn’t supporting the recent (and secure) key algorithms. If you connect from a client without the correct set of ciphers available, so the client and the server can come to some agreement on a mutually supported cipher set, you’ll see an error such as: If … Read more

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 … Read more

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 … Read more

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 … Read more

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 … Read more

SSLScan for Website SSL Diagnostics

Had an issue where we had a client that couldn’t access a particular site, in this case we wanted to determine what encryption ciphers a particular website was offering on its HTTPS server, SSLScan which is a Linux tool available on Ubuntu and other distributions can help, for example:

How to Check Domain NS Glue Records (using DIG)

The resolution of a DNS FQDN requires a number of servers to be queried, typically your machine (or a DNS resolver – on your behalf) will query the root DNS (name) servers, these will then return the (registrar) name servers that serve the TLD (top level domain) e.g. .com, .co.uk etc. for your domain, these … Read more