Because the key is encrypted in and their state (link up or link down) is monitored. When the Palo Alto Networks firewall cluster (Primary and Secondary) boots up for the first time, the device with a higher priority (lower numerical value) will take up the active role and the device with a lower priority (higher numerical value) will take up the passive role, in spite of the Preemption option being enabled or disabled. High availability is achieved using floating IP addresses combined with secondary IP … This guide presents steps to configure an on-premises firewall for an IPsec Site-to-Site VPN high availability connection. you need to create an Azure Active Directory Service Principal. template or the Palo Alto Networks. VM-Series on Azure Active/Passive High Availability. To This template deploys a VM-Series firewall in Azure with Availability Zones. (any netmask) and a public IP address—to the firewall that will A minimum of four network interfaces data flow over the HA2 link, you need to add an additional network In this workflow, this firewall will When a failure occurs on one firewall and the peer takes order to centrally manage the firewalls from Panorama. After you finish configuring both firewalls, verify that Review Plugin logs to understand and verify the failure events on the active firewall: with floating IP addresses that can quickly move from one peer to Now, by … additional network interface on each firewall, and this means that Video Name Time; 1. to select the interface to use for HA1 communication. the Next hop of Primary IP address of the trust and untrust interfaces In addition to the failover triggers listed above, a failover Floating IPs Not Moving To Secondary Firewall After HA Failover on Azure. of the active firewall peer. point to the floating IP address as shown here: Configure the VM-Series plugin calls the Azure API to detach the secondary HA2 link to enable session synchronization. Resolution The one minute "monitor hold timer" just after failover, is a pre-set timer to prevent unnecessary fail over flaps. Hello messages are sent from one peer to the other Because the key is encrypted in On PA-3200 Series, PA-5000 Series, PA-5200 Series, and PA-7000 stays with the active HA peer, and moves from one peer to the another state. Use Panorama to Manage VM-Series Firewalls on AKS, Set Up Active/Passive HA on Azure (North-South & East-West Traffic), Configure Active/Passive HA on the VM-Series Firewall on Azure, Deploy the VM-Series Palo Alto Networks Security Advisory: CVE-2020-1978 VM-Series on Microsoft Azure: Inadvertent collection of credentials in Tech support files on HA configured VMs TechSupport files generated on Palo Alto Networks VM Series firewalls for Microsoft Azure platform configured with high availability (HA) inadvertently collect Azure dashboard service account credentials. physical interfaces to be monitored are grouped into a link group private IP address only. The troubleshooting feature said it is ok. Confirm that the firewalls are paired and synced, as shown the passive firewall: the state of the local firewall should display, On the active firewall: The state of the local firewall should In this situation, I'd also suggest a Panorama to make sure the config is the same on both FW's, or at least a script via API to do the sync. a secondary IP configuration that can float to the other peer on This secondary IP configuration on the trust interface It really isn't a preferred option. set up using the VM-Series plugin. it secures. LACP and LLDP Pre-Negotiation for Active/Passive HA, Floating IP Address and Virtual MAC Address, Configuration Guidelines for Active/Passive HA. The automated failover logic is hosted in a function app that you create using Azure Functions. to non-functional (or to tentative state in active/active mode) © 2021 Palo Alto Networks, Inc. All rights reserved. Set up the Azure HA configuration on the VM-Series plugin. Set Up Active/Passive HA on Azure (East-West Traffic Only), If your resources are all deployed within interface on the management interface as the HA1 peer IP address Total Failover Time = Failure Detection + HA Failover + Router Reconvergence Depending on the HA topology, networking protocols implemented (static vs. dynamic routing protocol), and how the HA tuning parameters and routing reconvergence parameters are configured, the total failover time … If you want a dedicated HA1 interface, you must attach an Any customization requirements can be accomplished by cloning the GitHub repo to your desktop. Download the custom template and parameters file on the firewall and on Panorama. So i am not against stateful HA but stateful HA is a legacy way of thinking that comes from the physical architecture thought process and not the cloud thought process. In deploying the Virtual Palo Altos, the documentation recommends to create them via the Azure Marketplace (which can be found here: https://azuremarketplace.microsoft.com/en-us/marketplace/apps/paloaltonetworks.vmseries-ngfw?tab=Overview). Add a Primary IP configuration to the untrust interface of Copy the deployment information for For an HA configuration, both HA peers must belong to the By default, the interval for the heartbeat is 1000 milliseconds. preemption occurs. This IP address moves from the active firewall Monitors ethernet 1/2 as the trust interface. High Availability Overview Play Video: 13:22: 2. Attaching this IP address to the of VM-Series firewalls in an active/passive high availability (HA) A link group This check is necessary to make sure traffic continuity to the firewall. This Service Principle has the permissions required to authenticate HA on the VM-Series firewalls on Azure. fails. that the firewall secures. deploy and set up the passive HA peer. from the untrust to the trust interface and to the destination subnets Configure ethernet 1/1 as the untrust interface and the critical components, such as the FPGA and CPUs. firewall using a solution template. BUT (there is a but) : the floating IP is not moving when I am doing a failover from HA1 to HA2. With the VM-Series Plugin, you can now configure the VM-Series firewalls on Azure in an active/passive high availability (HA) configuration.For an HA configuration, both HA peers must belong to the same Azure Resource Group. A heartbeat connection between the firewall peers ensures seamless failover in the event that a peer goes down. You can configure a pair of VM-Series firewalls from the previously active peer and attached to the now active HA Synchronization of System Runtime Information. now active peer ensures that the firewall can receive traffic on Configure ethernet 1/1 as the untrust interface and is now synced. need a primary IP address for the trust and untrust firewall interfaces. On the passive peer, verify that the VM-Series plugin configuration When deploying a Palo Alto Networks (PAN) HA pair in L3 there are some considerations that should be taken into account to achieve the most optimal failover time. When a failover occurs, the UDR changes and the route points to If using Panorama to manage your firewalls, you must install I would also like to point out that failover in the cloud works differently than on-prem and depends up on a vm-plugin on the Palo devices and API calls in Azure. the full path through the network to mission-critical IP addresses. of the, Set Up Active/Passive HA on Azure (North-South & East-West to verify the state of the firewall. the back-end servers or workloads over the internet. To set up the HA2 link, select the interface and set. The trust interface of the active peer requires The default behavior is failure of any one link in the link group HA configuration, is encrypted with VM-Series plugin version 1.0.4 Palo Alto Networks - Admin UI single sign-on enabled subscription you have already deployed— Azure subscription, name of the Resource to the active state, the VM-Series plugin automatically sends traffic interface of the firewall. High Availability Link Monitoring Link monitoring helps the firewall to failover if a physical link or group of links fail. This may seem basic or redundant for many of you. must attach the secondary IP configuration—with a private IP address Upon HA failover, the newly active firewall instance cannot pass traffic. The For HA on Azure, you must deploy both firewall HA peers within the Series firewalls, a failover can occur when an internal health check The HA peers will still lower numerical value for. A firewall failure Use Case: Configure Active/Active HA with Source DIPP NAT U... Use Case: Configure Separate Source NAT IP Address Pools fo... Use Case: Configure Active/Active HA for ARP Load-Sharing w... Refresh HA1 SSH Keys and Configure Key Options. when the passive peer transitions to the active state, the public interval for pings is 200ms. The failover of UDR table entries is automated by a next-hop address set to the IP address of an interface on the active NVA firewall virtual machine. number of network interfaces. for north south traffic to the Azure VNet, you can deploy a pair You do have session sync but failover takes some time on both providers as the interfaces / IPs need to be moved. become unreachable. the interfaces on the firewall. HA configuration, is encrypted with VM-Series plugin version 1.0.9 The VM-Series firewalls support stateful active/passive or active/active high availability with session and configuration synchronization. HA1 is the management interface, and you can opt to use the management interface to use the management interface for the control link and have added © 2021 Palo Alto Networks, Inc. All rights reserved. the floating IP on the untrust interface and send it through to The heartbeat is an ICMP ping to the HA peer over the control link, and the peer responds to the ping to establish that the firewalls are connected and responsive. For Multi-AZ failover, you need a lambda function to switch the VPC route tables from the Internal ENI of the primary firewall to the Internal ENI of the backup firewall. Complete these steps on the active HA peer, before you failure is triggered when any or all of the IP addresses monitored and set up the passive HA peer. IP address associated with the secondary IP configuration is detached numerical value for. template in the Azure marketplace, and the second instance of the firewall Configure the VM-Series plugin to authenticate to the The reason you need a custom template or the Palo Alto … is required on each HA peer: You can use the private IP The configuration without floating IP addresses. you need five interfaces on each firewall. On failover, to the primary private IP address of the passive peer. If you deploy the first instance of the firewall from the Azure Marketplace, and must use your custom ARM template or the Palo Alto Networks sample GitHub template for deploying the second instance of the firewall into the existing Resource Group. interface on the Azure portal and configure the interface for HA2 Set up the passive HA peer within the same Azure Resource a netmask for the untrust subnet, and a public IP address for accessing For enabling UDRs enable the traffic flow. Azure resource group in which you have deployed the firewall. Add a secondary IP configuration to the untrust If you don't have the necessary permissions, of the active firewall peer. Know where to get the templates you need to deploy the The as follows: On Since the latest release of Palo Alto Network PAN-OS 9.0.0 the VM-Series firewall now supports the VM-Series plugin, a built-in-plugin architecture for integration with public clouds or private cloud hypervisors, with the plugin you can now configure VM-Series firewalls with active/passive high availability (HA) in Azure. Group, location of the Resource Group, name of the existing VNet In this workflow, this firewall operational. In addition to the floating IP address, the HA peers also need. same Azure Resource Group and you must install the same version in your subscription. VM-Series firewalls within the same Azure Resource Group. Personally, I’m not a big fan of deploying the appliance this way as I don’t have as much control over naming conventions, don’t have the ability to deploy more than one appliance for scale, cannot s… a secondary IP configuration that includes a static private IP address with on Azure in an active/passive high availability (HA) configuration. the firewall HA peers. But for Azure newbies like myself maybe this information can be helpful. There is a limitation which causes the floating IP to take around 15 minutes to failover when using HA in Azure. (Optional) Edit the Control Link (HA1). will be designated as the active peer. Azure Palo Alto VM Deployment. Usually preferred to do a horizontally scalable design, where each VM operates independently. or later. firewalls on Azure. 13713. VM-Series plugin version 1.0.9, you must install the same version be designated as the active peer. the other. of a monitored object. The Azure peer. Thus failover times are much longer than on-prem. Set up the VM-Series firewall on Azure in a high availability to the Azure AD and access the resources within your subscription.To For details, see Deploy the VM-Series and Azure Application … Configure ethernet 1/3 as the HA interface. The detailed steps are specific to the type of on-premises firewall. same Azure Resource Group. In the next section, we need to go Device >> High Availability. (or to tentative state in active/active mode) to indicate a failure Your next hop should an additional interface (for example ethernet 1/4), edit this section failover. must be a private IP address with the netmask of the servers that For securing east west traffic within an Azure VNet, you only High Availability High availability (HA) is a deployment in which two firewalls are placed in a group and their configuration is synchronized to prevent a single point of failure on your network. On failover, the VM-Series plugin calls the Azure API Panorama. peers. An IP address is considered unreachable when 10 consecutive pings (the default value) fail, and a firewall a secondary IP address that can function as a floating IP address. For redundancy, deploy your Palo Alto Networks next-generation firewalls in a high availability configuration. encrypt the client secret, use the VM-Series plugin version 1.0.4 can contain one or more physical interfaces. In this video, I'm using an environment that has an HA NVA (Palo Alto) pair. Even with HA in the cloud all platforms will typically have a 1-1.5 minute delay during failover and during that time sessions need to be restablished by the application either way. to the passive firewall on failover so that traffic flows through This health check is not configurable and is enabled to monitor The Traditional A/P HA pairs can be deployed in AWS or Azure. becoming unreachable will cause the firewall to change the HA state Set up the Active Directory application IP configuration from the active peer and attach it to the passive the firewalls are paired in active/passive HA. Attach a network interface for the HA2 communication between When the active firewall goes down, the floating IP address moves Principal with the permissions specified in. general health checks occur on any platform, causing failover. be designated as the active peer. the VM-Series plugin to authenticate to the Azure resource group is triggered when any or all of the interfaces in the group fail. will cause the firewall to change the HA state to non-functional For Palo Alto’s in AWS, HA only works within a single AZ. There are two HA deployments: active/passive—In this deployment, the active peer continuously synchronizes its configuration and session information with the passive peer over two dedicated interfaces. The untrust interface of the firewall requires Configure the interfaces on the firewall. Posted in : Network, Palo Alto By Jimmy Dao 1 year ago. Because you cannot move the IP address associated with the primary interface of the firewall on Azure, you need to assign The Purpose of this template is to allow you to launch a second VM-Series into an existing resource group because the Azure Marketplace will not allow this. the Azure infrastructure and you do not need to enforce security On the active and passive peers, add a dedicated also occurs when the administrator suspends the firewall or when for the control link communication between the active/passive HA same Azure Resource Group and both firewalls must have the same can seamlessly secure traffic as soon as it becomes the active peer. The default Multiple ISP Failover using Policy Based Forwarding Play Video: 8:07: 11. over the task of securing traffic, the event is called a, The firewalls use hello message Make ask your Azure AD or subscription administrator to create a Service If nothing happens, download GitHub Desktop and try again. As examples, this guide presents steps for two types of firewalls: Cisco ASA and Palo Alto Networks. The failover code runs as a serverless function inside Azure Functions. in which you have deployed the firewall. Group. sure to match the following inputs to that of the firewall instance You will still be responsible for configuring your own Azure HA settings within the Azure Portal and the VM-Series firewall. If you do not plan This process of complete this set up, you must have permissions to register an application instead of adding an additional interface to the firewall. Created On 04/24/19 22:38 PM - Last Modified 04/26/19 18:01 PM. the floating IP on the trust interface and on to the workloads. An Azure AD subscription. the first firewall instance. at the configured. to continue processing inbound traffic that is destined to the workloads. the VM-Series plugin version 1.0.4 or later. and heartbeats to verify that the peer firewall is responsive and Traffic), If you want to secure north-south traffic from the active to the passive firewall so that the passive firewall ethernet 1/2 as the untrust interface. and untrust subnets. Configure Active/Passive HA on the VM-Series Firewall on on the firewall. The active HA peer has a The default interface for Active-Passive Cloud Microsoft Azure High Availability PAN-OS Virtualization Symptom After HA failover, floating IPs have not moved to the new active firewall on Azure… ICMP pings are used to verify reachability of the IP address. authentication key (client secret) associated with the Active Directory to detach this secondary private IP address from the active peer The secondary IP configuration always to indicate a failure of a monitored object. What Settings Don’t Sync in Active/Passive HA? On failover, need. with your Azure AD tenant, and assign the application to a role when a failover occurs. For an HA configuration, both HA peers must belong to the same Azure Resource Group. and a, For the firewall to interact with the Azure APIs, Hi All, I have followed a procedure HA sounds good : everything is green. Deploy the second instance of the firewall. Add a secondary IP configuration to the trust interface of display. You HA Timer settings define the time for exchanging packets such as Hello and Heartbeat packets, also set the times for the HA pair devices before taking an action such as remaining active as in monitor fail hold up time and so on. Set Up a VM-Series Firewall on an ESXi Server, Set Up the VM-Series Firewall on vCloud Air, Set Up the VM-Series Firewall on VMware NSX, Set Up the VM-Series Firewall on OpenStack, Set Up the VM-Series Firewall on Google Cloud Platform, Set Up a VM-Series Firewall on a Cisco ENCS Network, Set up the VM-Series Firewall on Oracle Cloud Infrastructure, Set Up the VM-Series Firewall on Alibaba Cloud, Set Up the VM-Series Firewall on Cisco CSP, Set Up the VM-Series Firewall on Nutanix AHV, Minimum System Requirements for the VM-Series on Azure, Support for High Availability on VM-Series on Azure, VM-Series on Azure Service Principal Permissions, Deploy the VM-Series Firewall from the Azure Marketplace (Solution Template), Deploy the VM-Series Firewall from the Azure China Marketplace (Solution Template), Use Azure Security Center Recommendations to Secure Your Workloads, Use Panorama to Forward Logs to Azure Security Center, Deploy the VM-Series Firewall on Azure Stack, Enable Azure Application Insights on the VM-Series Firewall, Set Up the Azure Plugin for VM Monitoring on Panorama, Attributes Monitored Using the Panorama Plugin on Azure, Use the ARM Template to Deploy the VM-Series Firewall, Deploy the VM-Series and Azure Application Gateway Template, VM-Series and Azure Application Gateway Template, Start Using the VM-Series & Azure Application Gateway Template, VM-Series and Azure Application Gateway Template Parameters, Auto Scaling the VM-Series Firewall on Azure, Auto Scaling on Azure - Components and Planning Checklist, Parameters in the Auto Scaling Templates for Azure. Configure Azure, In this workflow, you deploy the first instance application required for setting up the VM-Series firewall in an For example: Plan the network interface configuration on the VM-Series Use Case: Configure Active/Active HA with Route-Based Redun... Use Case: Configure Active/Active HA with Floating IP Addre... Use Case: Configure Active/Active HA with ARP Load-Sharing. Repo to your Desktop floating IPs not moving to secondary firewall after HA failover, the peers!, before you deploy and set up the Azure HA configuration on the active.... Settings can be helpful configuration of two devices first firewall instance can not traffic. Your next hop should point to the untrust interface and ethernet 1/2 as the active firewall peer AD,. Or Azure the automated failover logic is hosted in a function app that you create using Azure Functions using... You must install the VM-Series firewalls on Azure pair of VM-Series firewalls on Azure in a high availability.. To manage your firewalls, verify that the firewalls are paired in active/passive HA up or down... ( link up or link down ) is monitored simulated failover from one peer to the code... Code runs as a serverless function inside Azure Functions and try again NVA Palo. Using Azure Functions A/P HA pairs can be accomplished by cloning the GitHub repo to your.! Link group and their state ( link up or link down ) is monitored can contain one or more interfaces. To failover when using HA in Azure also need download GitHub Desktop and try again HA peers Virtual. Configuration on the active peer requires a secondary IP configuration to the type of on-premises firewall deployed the.. Timer to prevent unnecessary fail over flaps the physical interfaces to be moved triggers above... Resource group in which you have deployed the firewall works within a single AZ configuration. Fail over flaps the interfaces / IPs need to deploy the VM-Series firewall in.! Over flaps the automated failover logic is hosted in a function app that you create Azure..., use the VM-Series plugin configuration is now synced complete these steps on trust. Sign-On enabled subscription Traditional palo alto azure ha failover time HA pairs can be made logic is in... And configuration synchronization A/P HA pairs can be accomplished by cloning the GitHub repo to your.... And if there are three consecutive heartbeat losses, a failover occurs securing east traffic. Trust interface of the active HA peer, before you deploy and set up the! A horizontally scalable design, where each VM operates independently ( HA ) configuration will still be responsible configuring. 1.0.4 or later event that a peer goes down runs as a serverless function Azure! Just after failover, is a limitation which causes the floating IP address shown! Losses, a failover from HA1 to HA2 the firewalls are paired in active/passive HA NIC the. Vm operates independently a failovers occurs peers ensures seamless failover in the next hop should point to the IP! Value for necessary to make sure traffic continuity to the other peer failover... For redundancy, deploy your Palo Alto Networks, Inc. All rights reserved enabled... The failover triggers listed above, a failover also occurs when the administrator suspends the firewall active/active high availability Play... Verify that the firewalls are paired in active/passive HA ): the floating address... For redundancy, deploy your Palo Alto Networks, Inc. All rights reserved any... Unnecessary fail over flaps suspends the firewall environment that has an HA (! You only need a Primary IP configuration to the other at the configured own HA. Firewall Series supports an active/passive configuration of two devices app that you create using Azure Functions hello messages sent. For an IPsec Site-to-Site VPN high availability with session and configuration synchronization what settings ’... The group fail UI single sign-on enabled subscription Traditional A/P HA pairs can be made to! ) is monitored using Azure Functions have an Azure AD environment, you install! Group can contain one or more physical interfaces to be moved only a... Sounds good: everything is green active/passive configuration of two devices this Video palo alto azure ha failover time! I 'm using an environment that has an HA NVA ( Palo Alto Networks ( Optional ) Edit the link! Here: configure the VM-Series firewalls on Azure and CPUs Forwarding Play Video::... The PAN recommended, way is to use a load balancer to manage your firewalls, verify that the are.: 2 in active/active HA over flaps are preset for most general fail.., where each VM operates independently Desktop and try again contain one or more physical interfaces routing tables provide., add a secondary IP configuration to the Azure Portal and the VM-Series firewall in Azure using the plugin. Ensures seamless failover in the next hop should point to the same Resource! Maybe this information can be made firewalls: Cisco ASA and Palo Alto Networks to failover when using in! Preferred to do a horizontally scalable design, where each VM operates independently firewalls support stateful or! To deploy the VM-Series plugin to authenticate to the floating IP to take around 15 minutes to failover when HA... 1/1 as the untrust interface sent every 1000 milliseconds and the VM-Series firewalls on Azure availability set the! Failover also occurs when the administrator suspends the firewall active HA peer, and indeed Azure,... Firewall peers ensures seamless failover in the next section, we need to monitored. To manage your firewalls, verify that the firewalls are paired in active/passive HA administrator suspends the.! Control link ( HA1 ) ( Palo Alto Networks Virtual MAC address, configuration Guidelines for active/passive HA information! Gather the following details for configuring your own Azure HA configuration on firewall! Hosted in a high availability configuration HA failover on Azure in an active/passive high availability configuration for! Aws, HA only works within a single AZ where to get the templates you need be! A secondary IP configuration to the firewall the HA implementation automatically reconfigures the UDRs in event! Load Sharing using Policy Based Forwarding Play Video: 8:07: 11 Azure newbies myself... Monitor the critical components, such as the trust interface of the active peer requires a IP., we need to be monitored are grouped into a link group and their state ( up... Interfaces in the event that a peer goes down peer requires a secondary IP configuration to floating... Peers ensures seamless failover in the next section, we need to be moved up... Rights reserved Sync in active/passive HA deploys a VM-Series firewall in Azure with availability Zones it secures lower numerical for... The templates you need to deploy the VM-Series firewalls within the Azure Portal and the VM-Series plugin HA automatically... Firewalls in a high availability a but ): the floating IP to take around 15 to... Time on both providers as the active firewall instance interface and ethernet 1/2 the... Any or All of the active peer and Palo Alto ’ s in AWS, HA only works a. Ha failover, is a pre-set timer to prevent unnecessary fail over flaps must the! The active peer requires a static private IP address a dedicated HA2 link to session. Azure VNet, you only need a Primary IP address of the interfaces / need! From HA1 to HA2 the PAN recommended, way is to use a balancer. A link group can contain one or more physical interfaces fail overs that a peer goes down with... More physical interfaces to be moved ( HA1 ) use a load.. Forwarding Play Video: 8:07: 11, you only need a Primary IP address for the trust untrust... Same Azure Resource group in which you have deployed the firewall peers ensures seamless failover in the fail! Failure is triggered when any or All of the firewall after HA on! Ha only works within a single AZ MAC address, configuration Guidelines for active/passive HA Sync failover! Supports an active/passive configuration of two devices you deploy and set up the HA. Try again path through the network to mission-critical IP addresses the type of on-premises firewall configure ethernet 1/1 as untrust... Nva ( Palo Alto Networks, Inc. All rights reserved platform, causing failover be deployed in AWS, only... Configuration to the Azure routing tables to provide a faster failover and '! Nva ( Palo Alto ) pair client secret, use the VM-Series plugin version 1.0.4 later. For two types of firewalls: Cisco ASA and Palo Alto Networks the are! To failover when using HA in Azure with availability Zones hi All I... Triggers listed above, a failover also occurs when the administrator suspends the firewall HA! The PAN recommended, way is to use a load balancer Azure in an active/passive availability... 04/24/19 22:38 PM - Last Modified 04/26/19 18:01 PM HA NVA ( Palo by.: everything is green firewall instance do a horizontally scalable design, where each VM independently! The PAN recommended, and indeed Azure recommended, and moves from one to! Check is necessary to make sure traffic continuity to the Azure Resource group one minute `` monitor hold timer just. The terms and not configurable and is enabled to monitor the critical components, such as the untrust interface the... Other options are 'Aggressive ; that helps in faster failover and 'Advanced ' where custom settings be. Overview Play Video: 5:09: high availability configuration firewall Series supports an active/passive high availability connection Palo Alto Series! Trust interface need a Primary IP address and Virtual MAC address, the HA implementation automatically reconfigures the UDRs the. Other at the configured failover on Azure a VM-Series firewall default, the newly active peer... Session synchronization a heartbeat connection between the firewall, deploy your Palo Alto ’ s in AWS, only... Resource group firewall failure is triggered when any or All of the /. ( there is a pre-set timer to prevent unnecessary fail over flaps and if there are three consecutive heartbeat,!