--- title: "protocols" tags: [ "Documentation", "networking" ] --- # Protocols | TCP | UDP | ICMP | |:-----------------|:-----------------|:------------------| |Transmission Control Protocol | User Datagram Protocol | Internet Control Message Protocol | | Reliable and slow. | Fast but unreliable, such as VOIP. Provides checksums. | Dirty checks such as pings. | # Networking Addressing ## IPv4 Three address ranges pertain only to private networks, so no computer looks beyond the local router to resolve them: 10.0.0.0 to 10.255.255.255 172.16.0.0 to 172.31.255.255 192.168.0.0 to 192.168.255.255 In theory, networks should fall within one of 3 ranges, depending upon their first octet: Class A 1-127 Class B 128 to 191 Class C 192 to 223 # Service Ports There are three types of port ranges: 1 to 1023: Well-known and established ports. 1024 to 49151 ICANN registered ports, used by various products, with limited oversight. 49152 to 65535 Dynamic ports for ad hoc use. View a more complete list of ports with: > less /etc/services # ip Show all addresses with: > ip a{dd{ress}} s{how} If a link's not present, load it with: sudo ip link set dev wlp3s0 up Add an interface to a device as so: > sudo ip a add 192.168.0.15/255.255.255.0 dev eth1 See network interfaces available on Fedora with: > less /etc/sysconfig/network-scripts/ifcfg-enp2s0f0 or on Debian with: > less /etc/network/interfaces Mostly, interfaces will receive automatic addresses from a DHCP server. If this hasn't happened for you, you can request a dhcp address with: > sudo dhclient eth1 View your current route to the internet with: > route ... although on void this is: > routel If you don't have a route to the internet, you can manually specify the default gateway with: > sudo route add default gw 192.168.0.1 ... or ... > sudo ip route add default via 192.168.0.1