Troubleshooting Networking - Paiet/Tech-Journal-for-Everything GitHub Wiki

-   Testing connectivity

    -   ping - Test server connectivity

    -   dig - Perform a DNS lookup

    -   nslookup - Perform a DNS lookup

    -   host - Perform a DNS lookup

-   Locating a bad hop

    -   traceroute - Display the path to a host

        -   sudo apt install traceroute

    -   tracepath - Test connectivity along the path

-   IPv6 versions of IPv4 tools

    -   ping6

    -   traceroute6

    -   tracepath6

-   Old Tools (net-tools)

    -   Binaries that pulled from various sources

    -   Configurations varied from distro to distro

    -   Common tools

        -   arp

        -   ifconfig

        -   netstat

        -   nameif

        -   route

    -   sudo apt install net-tools

-   New Tools (iproute2)

    -   Queries the Linux Kernel API (netlink)

    -   Consistent behavior between distros

    -   More efficient

    -   Common tools

        -   ip

        -   ss (socket statistics)

        -   routel

    -   sudo apt install iproute2

-   Verify IP Addressing

    -   ifconfig / ip addr

        -   Display information about network interfaces

-   Verify Routing Table

    -   route / ip route/ routel

        -   Display and manipulate the routing table

-   Verify sessions are present

    -   netstat / ss - Display network connections

        -   netstat -atp (All sessions)

        -   netstat -tp (Active sessions)

        -   netstat --route displays routing table

        -   netstat --program attempts to display software using ports