Operation and Maintenance
Linux Operation and Maintenance
How to find the IP address of a Linux server? (ifconfig and ip addr)
How to find the IP address of a Linux server? (ifconfig and ip addr)
推荐使用ip addr命令查看Linux服务器IP地址，其中ip -4 addr显示IPv4地址，inet后数字即为IP；ifconfig已弃用，若需使用须先安装net-tools工具包。
To find the IP address of a Linux server, use either ifconfig or ip addr — but note that ifconfig is deprecated on many modern systems and may not be installed by default. The ip addr command is the current standard and more reliable.
Check with ip addr (recommended)
This is the preferred method on most modern Linux distributions (like Ubuntu 18.04 , CentOS 7 , Debian 9 ). Run:
-
ip addr— shows all interfaces and their IPv4/IPv6 addresses -
ip -4 addr— shows only IPv4 addresses (cleaner output) -
ip -4 addr show eth0— replaceeth0with your interface name (e.g.,ens33,enp0s3) to see just that interface’s IPv4 info
Look for the line starting with inet — the number right after it (e.g., inet 192.168.1.20/24) is your server’s IPv4 address. The /24 is the subnet mask, not part of the IP.
Use ifconfig (if available)
Some older or minimal installations still have ifconfig, but it’s often missing from fresh installs. If you get command not found, install it first:
- On Debian/Ubuntu:
sudo apt install net-tools - On RHEL/CentOS/Fedora:
sudo yum install net-toolsorsudo dnf install net-tools
Then run ifconfig and look for the inet field under your active interface (e.g., eth0 or ens33). Ignore 127.0.0.1 — that’s localhost.
Quick one-liners for scripts or remote checks
These extract just the primary IPv4 address (useful in automation):
-
hostname -I— prints all IPv4 addresses space-separated (simplest for basic use) ip -4 addr | grep -oP '(? — grabs the first IPv4 address from <code>ip addr-
ip route | grep 'src' | awk '{print $9}'— shows the IP used for outbound traffic (often the main server IP)
What to watch out for
Don’t assume eth0 is always the right interface — modern systems use predictable interface names like ens33, enp0s3, or ens1f0. Look for an interface with UP status and a non-127.0.0.1 inet address. Also, ignore inet6 lines unless you specifically need IPv6.
Basically, ip addr is the go-to. It’s built-in, consistent, and actively maintained — no extra packages needed.
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