The Internet and Hosting Providers

The Internet:

• A term used to collectively describe the interconnected heterogenous networks that route packets worldwide using Internet Protocol (IP).

Domain Name System (DNS):

• A Domain Name System (DNS) server, among other things, resolves Uniform Resource Locator (URL) style names into IP v4/v6 addresses or points to the DNS server that can. DNS servers normally operate over TCP and UDP using port 53. Client lookups normally use UDP but can fallback to TCP. TCP vs UDP
• Examples: BIND, Microsoft's DNS Server
• Comparison of DNS server software

Patches and xdelta3

"Patches" are small scripts that take an existing file, a difference file (patch.vcdiff) and create a new file based on those differences. This is usually done using a program called xdelta3 which implements RFC 3284.

Concept: FileA + differences.vcdiff = FileB

Usually a shell language is used for the actual script like batch and/or bash and the patch bundle includes the xdelta3 binary.

Use Cases:

Patches are typically used when needing to make very small changes to very large files in a binary exact way (the hash of newFileB must match the hash of originalFileB).

BitTorrent Tracker Theory

BitTorrent Trackers are Hyper Text Transfer Protocol (HTTP) or User Datagram Protocol (UDP) servers that keep a list of peers associated with an info_hash and return that peer_list when queried. Thus, at their core, trackers have no knowledge of the files clients are exchanging. Some trackers are configured to only keep peer_lists for certain info_hashes (registered torrents) or to only return the peer_list to certain query requests (registered peers). In common parlance, some websites operate as front-ends for tracker software so are referred to as "trackers." This is technically incorrect, but this diction shall be used going forward.

Prerequsite: Introduction to BitTorrent Protocol, Beginner's Guide, WikiBooks, Wikipedia

Internet Relay Chat (IRC) and Kludges

Internet Relay Chat (IRC) is an archaic protocol developed in the days where mail servers, newsgroups and BBSes were common (e.g. predates HTTP and the web). The idea behind the protocol, like others of its time, is that clients would have their textual messages relayed by a centralized server to other clients, with the innovation of IRC being that it supported real-time multi-user communications (BBSes were sometimes single user and mailservers/newsgroups asynchronous).

While it is unfortunate that electronic mail is here to stay, BBS, newsgroups and IRC are luckily just about dead.