The ramblings of a computer geek
So, finally BT Openreach had got round to installing fibre optic cabling to the local area to provide fibre optic based Internet. If you’re interested to know if you can get (or if not register your interest) by using the https://www.openreach.com/fibre-broadband site. You might ask, what do you mean fibre Internet? I already have fibre … Read more
In this scenario I had a pair of Palo Alto Firewalls that were providing firewall services as a perimeter pair of firewalls acting in an active/passive cluster. Due to our internal network configuration, use of OSPF etc. the interfaces (ports) on the passive firewall were set to be down/disabled when that firewall was not active. … Read more
I’m currently in the process of moving from FTTC broadband to FTTP broadband, as part of this there is no copper telephone line because its fully fibre optic based. At the time of writing my ISP (plus.net) did not offer their own VOIP telephone service you could port your telephone number to, meaning in the … Read more
I recently came across an odd problem with the links from our Extreme Networks X695 switches to some Dell S5148F-ON switches, the X695 was running: 30.7.2.1, the Dell switch 10.4.3.6C1. Essentially what started the oddity was a transceiver failure. The equipment has been in production for a few months, all was working well. Suddenly a … Read more
Very occasionally a QSFP+ port might not be the correct form factor, what if you have a switch with only QSFP+ ports e.g. an Extreme Networks X770 but you need to connect up a device with an SFP+ port. Well, although you’ll be wasting a QSFP+ port this may help you. Extreme Networks provide what … Read more
The QSFP+ or QSFP28 ports of the Extreme Networks switches can be partitioned, what this means is you can make a 40Gbit QSFP+ port appear as 4 x 10Gbit SFP+ ports, however you’re require a suitable QSFP+ module for example with MTP port and a fan-out cable to split that MTP into 4 x LC … Read more
The OSI Model (Open Systems Interconnection) model is a set of rules and requirements to model and conceptualise the communication between two (network) systems. Yes, its theory, but in computing and networking it can be useful to use as a basic guide when troubleshooting. It helps you to rule-in or rule-out where a problem might … Read more
A fairly simple approach to providing uplink resilience. There are methods like EAPS or MLAG to give you uplink resilience, but sometimes you just need something simple. A redundant physical (or “Redundant Phy”) is essentially two uplinks to upstream switches and to avoid a loop, the downstream switch (i.e. the one with the redundant phy … Read more
The 5520-VIM-4YE, this has 4 x SFP28 ports 10/25. You can use 10Gbit or 25Gbit speeds on these ports. On an Extreme 5520 Universal hardware switch this will be ports 57-60 (on 48port model) or 33-36 (on a 24 port model) If you want to use 4 x SFP+ modules running at 10Gbit, you need … Read more
Emails crossing the internet use secure connections encrypted using Transport Layer Security (TLS). However, there remain vulnerabilities in this method of protecting the confidentiality of emails, whereby a person-in-the-middle can trick incoming connections to send to another server and/or send information in the clear. MTA-STS is a standard designed to address these vulnerabilities and is … Read more