# Instance Failing to Initialize Networking (Unable to Receive DHCP Response)

## Problem

* Instance is failing to boot or be reachable.
* No DHCP reply is received.
* DHCP request is observed on both the physical (e.g. bond0) interface of both the hypervisor, and designated DHCP agent host(s).

## Environment

* Platform9 Managed OpenStack - All Versions

## Cause

Either on which the hypervisor on which the instance resides, or one of the associated hosts of the designated DHCP agents for the given network, the Linux/OVS bridge which is defined as part of the bridge\_mappings variable in `/opt/pf9/etc/pf9-neutron-ovs-agent/ml2.conf` is either invalid, or the bridge has no associated physical interface (e.g. bond0).

## Resolution

1. Ensure that `bridge_mappings` in the `/opt/pf9/etc/pf9-neutron-ovs-agent/ml2_conf.ini` configuration file on the affected host (whether the hypervisor, or DHCP host) has the correct physical interface name specified.
2. If it has been modified, restart the `pf9-neutron-ovs-agent` service.
3. Otherwise, ensure the physical interface is added to the specified interface, e.g.

{% tabs %}
{% tab title="Bash" %}

```bash
ovs-vsctl add-port br-pf9 bond0
```

{% endtab %}
{% endtabs %}