# DHCP: Address conflict detected for 192.168.1.100, disabling interface eth0

- **ID:** `networking/dhcp-address-conflict`
- **Domain:** networking
- **Category:** network_error
- **Verification:** ai_generated
- **Fix Rate:** 85%

## Root Cause

The DHCP client received an ACK for an IP address, but then detected another host using the same IP via ARP probe, causing the client to release the address and disable the interface to avoid IP conflicts.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| ISC DHCP client 4.4-4.5 | active | — | — |
| systemd-networkd 250-256 | active | — | — |
| dhcpcd 9.4-10.0 | active | — | — |
| Linux kernel 5.15-6.8 | active | — | — |
| Windows 10/11 DHCP client | active | — | — |

## Workarounds

1. **Release and request a new IP: `dhclient -r eth0; dhclient eth0` to get a different address from the pool.** (70% success)
   ```
   Release and request a new IP: `dhclient -r eth0; dhclient eth0` to get a different address from the pool.
   ```
2. **Identify the conflicting host by checking ARP table: `arp -a | grep 192.168.1.100` and remove it from the network, or exclude that IP from the DHCP pool on the server.** (85% success)
   ```
   Identify the conflicting host by checking ARP table: `arp -a | grep 192.168.1.100` and remove it from the network, or exclude that IP from the DHCP pool on the server.
   ```
3. **Configure a DHCP reservation on the server for the client's MAC address to ensure it always gets the same IP and avoid conflicts.** (90% success)
   ```
   Configure a DHCP reservation on the server for the client's MAC address to ensure it always gets the same IP and avoid conflicts.
   ```

## Dead Ends

- **Setting a static IP on the client without checking the DHCP pool** — The static IP may still conflict with the DHCP server's pool, leading to the same error or network instability. (80% fail)
- **Restarting the DHCP client repeatedly (e.g., `dhclient -r && dhclient`)** — The conflicting host is still on the network; the same IP may be reassigned, causing immediate conflict again. (85% fail)
- **Ignoring the error and assuming it's a one-time glitch** — The interface remains disabled, so the client has no network connectivity until manually re-enabled. (95% fail)