Why do i require self ip and floating ip ? if i am configuring HA and have 5 VLANS in active device , do i need to have 5 floating IPs ?

Why do i require self ip and floating ip ? if i am configuring HA and have 5 VLANS in active device , do i need to have 5 floating IPs ? or can't i have one floating IP in my active device to have HA configured for entire box ?Is this floating IP common across both active/standby unit ?

The floating IP is a virtual address to access the active device. Do you know VRRP? It looks like VRRP! Depending on your configuration you need it or not. Note that all virtual server addresses behave like floating IPs.

asking the question once is enough i believe :)

you don't need it, without it nothing will break directly. but things will become complex. if you for example have a server with the big-ip as default gateway, what IP do you configure? you have to choose one, so either unit A or unit B. if you have a floating Self IP that IP moves to the active unit, so you can use that one.

similar with traffic from the BIG-IP to your server. without a floating self IP it will use the non floating self IP, which will change with a failover, perhaps causing issues.

so no you don't NEED it, but it makes things much nicer.

When do you need self IP? Self IPs are used for:

• Monitors (source address is Appliance Self IP)
• Connection to backend servers (how to route traffic to server if you do not have IP?)
• Need to create a floating IP... local self IP is required to create floating IP.

When do you need floating IP? Floating IPs are used for:

• routing needs as explained by boneyard
• SNAT automap use egress floating ip, self ip if no floating is defined

When do you not need self IP?

• There is no need to create self IP on external VLAN if there is no outbound connections. A virtual server does not need self IP. VS use auto last hop to route response without route and self IP.

When do you not need floating IP?

• If SNAT pool is used instead SNAT automap, floating IP is not needed on internal VLAN