Linux networking & DNS
Inspect addresses, routing, DNS, IPv4 and IPv6, reachability and targeted network traces.
How do I find the IP addresses and interfaces on my Linux server?
Identify Linux server interfaces, IPv4 and IPv6 addresses, and link status without changing the network configuration or interrupting SSH.
Read the answer Linux networking & DNSHow do I check the default gateway and route used by my Linux server?
Inspect the Linux default route and selected path to a destination, including source addresses, policy routing and missing gateway symptoms.
Read the answer Linux networking & DNSHow do I see which services are listening on a Linux server?
Use ss to inspect TCP and UDP listeners, identify owning processes and distinguish loopback-only services from publicly bound addresses.
Read the answer Linux networking & DNSWhy does a Linux application resolve a hostname differently from dig?
Compare Linux application name resolution with direct DNS queries and locate hosts-file, NSS, caching or split-DNS differences safely.
Read the answer Linux networking & DNSHow do I check A, AAAA, MX, TXT and reverse DNS records from a server?
Inspect a domain’s DNS records and reverse lookup from Linux, then compare authoritative answers and cached resolver results during changes.
Read the answer Linux networking & DNSHow do I inspect the DNS servers used by systemd-resolved?
Read systemd-resolved DNS servers, per-interface routing domains and query results without replacing managed resolver configuration files.
Read the answer Linux networking & DNSHow do I test basic reachability and packet loss from a Linux server?
Run bounded Linux ping tests, interpret round-trip time and packet loss, and separate ICMP filtering from an actual application outage.
Read the answer Linux networking & DNSHow do I trace a Linux server’s network path and investigate MTU problems?
Use tracepath to inspect a network path and discover possible path MTU issues while recognising filtered hops and asymmetric routing.
Read the answer Linux networking & DNSHow do I find out whether a server problem affects IPv4 or IPv6?
Compare IPv4 and IPv6 addresses, routes, DNS records and HTTPS behaviour to diagnose failures that affect only one network family.
Read the answer Linux networking & DNSHow do I capture a small, targeted network trace on a Linux server?
Capture a bounded connection trace with tcpdump, limiting the peer, port and duration while avoiding unnecessary packet payload collection.
Read the answerNo matching question in this topic. Try a shorter phrase or search all server questions.