Don’t Block ICMP
“Don’t ping my server!” — is the sentiment among many sysadmins, and usually leads to a full-on ICMP blocking. But, it’s a terrible idea. Here’s why.
Forwarding IP traffic through a VPN
You have two servers and want to serve the traffic for an IP address on one server from another server?
Fundamentals: The Address Resolution Protocol
How does a computer know what MAC address belongs to an IP? How does ARP work?
Fundamentals: The Internet Protocol
How do you scale a network to global proportions? The answer is the Internet Protocol. Let’s dive into it.
Fundamentals: VLANs explained
How do you run multiple networks over the same physical network? How do virtual LANs work?
Fundamentals: Ethernet explained
Ethernet is one of the most fundamental protocols underpinning todays internet. It is so fundamental that we often take it as granted and don’t even think about it.