SpamAssassin is a popular anti-spam program. It is run on the server and checks all emails as they come it. It looks for a large number of different aspects, and then gives each email a score of how likely it is that that email is spam. If the score is above a certain number, then…
A fiber optic connection depends on the speed of the switch/router, the speed that light can travel through the cable, and also on the optic on each end of the cable. A dysfunctional optic can cause errors on a port, or worse, bring down the whole connections. I have run into plenty of times when…
To configure Ipv6 on multiple domains on an nginx server you must include the listen [::]:80; line in every server. The trick is to also include listen [::]:80 default_server ipv6only=on; onto the server server/domain that nginx is listening to. Here is an example configuration with two sites both of which respond to IPv4 and Ipv6:…
The Cisco command ‘ip nat outside’ is used to configure the IP address and interface that will be used for outbound Network Address Translation (NAT). This command is typically used in conjunction with the ‘ip nat inside’ command, which specifies the IP address and interface used for inbound NAT. The ‘ip nat outside’ command allows…
The ‘ip nat inside source list [number] interface [interface name] overload’ command is used in Cisco routers to configure a source NAT (Network Address Translation) rule for outbound traffic from a specific interface to the Internet. This command allows you to translate the source IP addresses of packets leaving the internal network to a different…
Linode is one of the top VPS providers in the market. They have a huge amount of customers at all levels, from the low end to enterprise. And for the last week or so they have been the target of a large number of DDOS attacks. These DDOS attacks are obviously not targeting any specific customer, but Lindoe…
Bulma is a modern CSS framework based on Flexbox. It uses many of the newest and best CSS features. It has a distinct feel and look and seems to pride itself on being widely different from older CSS frameworks, like Bootstrap. This is great in a lot of ways, and Bulma might be a good…
Most VPS providers have an hourly billing rate and then a monthly billing limit. This may be something like $0.015 per hour or $10/month. So if you only use your VPS for a few hours a month, will you be charged only a few cents? Maybe. So the way a VPS works is that when you sign…
Colocation and datacenter cabinets and racks are measures in rack units. The height of a cabinet is a set number of rack units. These rack units are usually represented by the letter “U”. A common datacenter cabinet height is 42U or 42 rack units. Servers are also measures in rack unit height. So you may…
UPDATE 2023: Virmach is not longer operating a valid service. They have stopped responding to tickets and their VPS instances are offline. Looks like the company has closed without informing customers. Virach is a low-end VPS provider. I had heard about them here and there for a few years, but recently began to see a…