{"id":341,"date":"2019-04-01T19:20:48","date_gmt":"2019-04-01T19:20:48","guid":{"rendered":"http:\/\/www.hoopchuk.org\/wordpress\/?page_id=341"},"modified":"2019-04-02T13:06:56","modified_gmt":"2019-04-02T13:06:56","slug":"code-stuff","status":"publish","type":"page","link":"https:\/\/www.hoopchuk.org\/wordpress\/code-stuff\/","title":{"rendered":"Code Stuff"},"content":{"rendered":"

Summary<\/h1>\n

Stuff I getted asked about on interviews. It’s a compilation of things I learned across talking to many folks about paying me to do what I find interesting and am passionate about. I can never directly thank these people stumping me and prompting me to keep on learning and growing and getting better … THANK YOU !!!<\/em><\/p>\n

TODOs<\/h1>\n

There are no “TODOs” I can think of on 01APR2019MON:<\/p>\n

    \n
  1. One<\/li>\n<\/ol>\n

    Networking<\/h1>\n

    Never ever have I talked with somebody and not had an exciting conversation about the various “network models” and “name the protocol” \ud83d\ude42<\/p>\n

    Protocols<\/h2>\n

    ICMP is a control protocol, meaning that it designed to not carry application data, but rather information about the status of the network itself. The best known example of ICMP in practice is the ping utility, that uses ICMP to probe remote hosts for responsiveness and overall round-trip time of the probe messages.<\/p>\n

    Both Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are transportation protocols, they are used to pass the actual data. The main difference between TCP and UDP is that TCP is a connection oriented protocol, it guarantees that all sent packets will reach the destination in the correct order.<\/p>\n

    UDP, on the other hand, is a connection-less protocol. Communication is datagram oriented, so the integrity is guaranteed only on the single datagram. Datagrams reach destination and can arrive out of order or don’t arrive at all. It’s generally used for real time communication, where a little percentage of packet loss rate is preferable to the overhead of a TCP connection.<\/p>\n

    Internet protocol suite<\/h2>\n

    Application layer<\/h3>\n

    BGP DHCP DNS FTP HTTP HTTPS IMAP LDAP MGCP MQTT NNTP NTP POP ONC\/RPC RTP RTSP RIP SIP SMTP SNMP SSH Telnet TLS\/SSL XMPP more…<\/p>\n

    Transport layer<\/h3>\n

    TCP UDP DCCP SCTP RSVP more…<\/p>\n

    Internet layer<\/h3>\n

    IP IPv4 IPv6 ICMP ICMPv6 ECN IGMP IPsec more…<\/p>\n

    Link layer<\/h3>\n

    ARP NDP OSPF Tunnels L2TP PPP MAC Ethernet Wi-Fi DSL ISDN FDDI<\/p>\n

    ICMP<\/h3>\n

    Internet Control Message Protocol<\/p>\n

      \n
    1. ping<\/li>\n<\/ol>\n

      UDP<\/h3>\n

      User Datagram Protocol<\/p>\n

        \n
      1. Domain Name System (DNS)<\/li>\n
      2. Simple Network Management Protocol (SNMP)<\/li>\n
      3. Routing Information Protocol (RIP)<\/li>\n
      4. Dynamic Host Configuration Protocol (DHCP)<\/li>\n<\/ol>\n

        TCP<\/h3>\n

        Transmission Control Protocol<\/p>\n

          \n
        1. World Wide Web (WWW)<\/li>\n
        2. email<\/li>\n
        3. File Transfer Protocol<\/li>\n
        4. Secure Shell<\/li>\n
        5. peer-to-peer file sharing<\/li>\n
        6. streaming media<\/li>\n<\/ol>\n

          Classless Inter Domain Routing<\/h2>\n

          CIDR – Classless Inter Domain Routing <\/p>\n

          Classless InterDomain Routing (CIDR) was invented to keep the Internet from running out of IP Addresses. The use of a CIDR notated address can easily represent classful addresses (Class A = \/8, Class B = \/16, and Class C = \/24).<\/p>\n

          Private Addresses<\/h2>\n

          There exist “ranges” of IP addresses that are reserved and you should know them in case you’re debugging stuff and you see for instance 192.168.1.100<\/code> which can’t be a “service on the web”.<\/p>\n