Quickly add a runtime IP to an interface for testing, maintenance or one-off services. 16.11.2025 | reading time: 2 min Need to test a service, check routing, or troubleshoot without changing system-wide settings? Add an address to an interface at runtime with the `ip` tool: it takes effect immediately and vanishes after a reboot unless made persistent. Show it in action As root or via `sudo` add an IPv4 address, verify it, then remove it when finished: ```ip addr add 192.0.2.100/24 dev eth0; ip addr show dev eth0``` The relevant line in the output will show the new address, for example ```inet 192.0.2.100/24 brd 192.0.2.255 scope global eth0``` To remove the address: ```ip addr del 192.0.2.100/24 dev eth0; ip addr show dev eth0``` and the address disappears from the interface immediately. Practical nuances to remember Adding an address at runtime is ephemeral by design; persistence requires editing your distro's network configuration or using NetworkManager; also add routes if the new address needs a specific gateway, and use `ip neigh` or `arping` to detect duplicates before committing to a test address. Options that matter You can assign multiple addresses to one interface, provide a label (legacy aliases), and select scope (global, link, host); for IPv6 be aware of preferred/temporary address behavior and privacy extensions that the kernel may manage automatically. Other ways to do it If the system uses NetworkManager prefer `nmcli` for runtime changes that integrate with the manager; older guides use `ifconfig` with aliases, and systemd-networkd or netplan require file changes for persistent assignments. Wrap-up and next step Temporary IPs are a safe, reversible tool for testing and quick fixes; master the runtime commands, then learn how to make changes persistent as the situation demands, and consider deepening Linux networking skills toward certifications like CompTIA Linux+ or LPIC-1 with intensive exam prep at bitsandbytes.academy. Join Bits & Bytes Academy First class LINUX exam preparation. network utilities troubleshooting scripting
