The ramblings of a computer geek
Sometimes SMTP servers what a particular EHLO/HELO argument for connecting clients, you can make Thunderbird do this by setting a new setting Settings->Config Editor, then add the following setting: mail.smtpserver.smtp1.hello_argument Specifying what you want Thunderbird to announce itself as.
If you want to use OpenSSL on Microsoft Windows, there are a number of packages provided that allow you to do this, in this example we’ll use Shinning Light Production’s OpenSSL MSI Package. Step 1 – Download and Install OpenSSL Download the installer from: https://slproweb.com/products/Win32OpenSSL.html, I used Win64 OpenSSL v3.3.3 Light, but there may be … Read more
A simple BASH script that you can run as a CRON job to check if a particular string is present in a file, and if not it sends you an email to say the file no longer has a particular string. And the email send just uses sendmail (assuming that is installed and configured). You … Read more
We needed to determine the “fingerprint” of a x509 certificate which was present within SAML2 XML Metadata as part of an update of the metadata during a swap from using Shibboleth IdP as our IdP with using OpenAthens IdP instead. You’ll need to have your own source Metadata from which you want to extract the … Read more
Although it may not be useful to most unless you are using the OpenAthens with Shibboleth IdP, I though running through some SAML request debugging which shows how you can take apart a SAML request, rewrite it and then re-encode it to assist in debugging or testing. The purpose of this was to test the … Read more
The Microsoft Exchange Poison Queue is a little known queue on an on-premise Microsoft Exchange Server, maybe I’ve been lucky, but I’ve only seen emails end up here once in my time using Exchange Server which goes back to Exchange 5.5. However this week, we observed some messages going into the Poison Queue which were … Read more
Was working recently with some colleagues on their coursework, where they had a need to configure a Cisco ASA Firewall to prepare a network topology that met certain criteria. They were using Cisco Packet Tracer, but were having a problem creating sub-interfaces (for each VLAN), it seemed that Cisco Packet Tracer (or the current version … Read more
During the preparation for a migration of the email service to Microsoft 365 Exchange Online, we were preparing a small test environment so we could step through what is required to faciltiate the links between Microsoft Active Directory, Microsoft Exchange on-premise and the Microsoft 365 cloud environment that includes Microsoft Exchange Online cloud hosted email. … Read more
We had a bit of an oddity on an Extreme Networks SwitchEngine (XOS) switch running: 32.7.1.9patch1-26, devices connecting to a specific VLAN that should be authenticated by Netlogin (NAC) via radius were failing giving the error below. Checking the switch, the VLAN very much existed, so it was a mystery why it said it wasn’t. … Read more
If you have a VLAN which used as the source of multicast streams there are considerations on how it is used specifically when you are “stretching” that VLAN across the fabric, i.e. you have the VLAN and router(s) for that VLAN on a particular distribution switch pair, but then you have the VLAN stretched across … Read more