Static IP Configuration: Assign Fixed IP to VPS

Static IPs stay the same—essential for servers, DNS records, firewall rules, and VPNs. Dynamic IPs (change on reboot) cause constant issues. Every VPS should have a static IP.

Why Static IP?

• DNS pointing: Your domain points to this IP—changing it breaks everything
• Firewall rules: Rules referencing the IP stay valid
• VPN/Tunnels: Require consistent IP for connections
• Mail servers: Depend on stable IP for reputation
• Remote access: SSH/RDP to known IP address

Check Current IP

ip addr show
# Output shows current IP, e.g., 192.168.1.100/24

hostname -I
# Quick IP check

Configure with Netplan (Modern)

Edit /etc/netplan/01-netcfg.yaml:

network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      dhcp4: no
      dhcp6: no
      addresses:
        - 192.168.1.100/24
      gateway4: 192.168.1.1
      nameservers:
        addresses: [8.8.8.8, 8.8.4.4]
      routes:
        - to: 0.0.0.0/0
          via: 192.168.1.1

Apply changes:

sudo netplan apply
# Test immediately:
ping 8.8.8.8

Debian/Ubuntu (/etc/network/interfaces)

Edit /etc/network/interfaces:

auto eth0
iface eth0 inet static
    address 192.168.1.100
    netmask 255.255.255.0
    gateway 192.168.1.1
    dns-nameservers 8.8.8.8 8.8.4.4

Restart networking:

sudo systemctl restart networking

CentOS/RHEL Configuration

Edit /etc/sysconfig/network-scripts/ifcfg-eth0:

BOOTPROTO=none
ONBOOT=yes
IPADDR=192.168.1.100
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
DNS1=8.8.8.8
DNS2=8.8.4.4

Restart networking:

sudo systemctl restart network

Verify Configuration

# Check IP is static
ip addr show eth0

# Test internet
ping google.com

# Check DNS
nslookup google.com

# Verify gateway
route -n

Update DNS Records

After changing IP, update your domain's DNS A record to point to new IP:

1. DNS provider (Cloudflare, Route53, etc.)
2. Find A record for your domain
3. Change IP to new static IP
4. Wait 24 hours for propagation (usually faster)

Troubleshooting

Related: Advanced VPS networking | DNS configuration | Firewall setup

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