Network

The server won’t resolve a domain, but pings fly through. No familiar dig at hand — the BIOS is already loading a minimal busybox. Or on a host without bind-tools. nslookup and drill fill this gap: the first one is built into almost everything, the …

When ifconfig returns nothing and configuring a route requires a separate command, that’s not a system bug. It’s iproute2 — the package that replaced net-tools in modern Linux distributions. The ip utility from iproute2 is the standard interface for …

Network issues hide well — interface is up, IP is assigned, iptables is quiet, yet packet loss or micro-freezes only surface under load. ethtool gives direct access to hardware state, driver behavior, and offload mechanisms that neither ip nor …

When debugging network issues in Linux infrastructure, ping and curl are not enough. Sometimes you need to see what is actually traveling over the wire. tcpdump is the standard tool for capturing packets from the CLI. tshark is its sibling from the …

When netstat hangs on a server with tens of thousands of connections, it’s time to switch to ss. Part of the iproute2 package, ss queries the kernel directly via netlink instead of parsing /proc/net/*. The result is instant output with minimal …

Ngrep applies grep-style pattern matching to network packets. When you need to see exactly what two services are exchanging over the wire and tcpdump drowns you in noise, ngrep isolates the payload content you care about. Installation Ngrep ships in …

Your VM in the cloud has no public IP or internet access is blocked via NAT, but the deployment needs wget/curl from inside. Squid on an intermediate host with a decent uplink solves this in ten minutes. Why This Is Needed I forward internet through …