MX75 HA

[CedricMX]

Hello team !

Need your help to clarify a point.

I will install 2 MX75 (primary and spare) on my locations. 

I will use the LAN side for VRRP messages. Each LAN MX75 port will be connected to a switch.

On the WAN side, i will use the virtual uplinks ips.

Can you help me to define the number of public ip address i will need.

From my understanding, i need these ip address :

MX1 :

WAN 1 (connected to ISP 1 router port 1)

• IP address : X.X.X.3
• Gateway : X.X.X.1

WAN 2 (connected to ISP 2 router port 1)

• IP address : Y.Y.Y.3
• Gateway : Y.Y.Y.1

MX2 :

WAN 1 (connected to ISP 1 router port 2)

• IP address : X.X.X.4
• Gateway : X.X.X.2

WAN 2 (connected to ISP 2 router port 2)

• IP address : Y.Y.Y.4
• Gateway : Y.Y.Y.2

ISP 1 VIP : X.X.X.5

ISP 2 VIP : Y.Y.Y.5

Do you think i need 5 public ip address per ISP for a transparent HA failover and failback ?

Many thanks for clarifying these point.

Regards.

[Mloraditch]

Yes generally on most ISPs you will need a block of 5 or a /29 if talking in subnets. Some ISPs do sell them individually and you could get away with just 3. Generally that's smaller, rural ISPs, but it does exist. I always go with 5 so I have extras available for vendor needs.

[CedricMX]

Thanks for your reply.

I will pay for a /29 subnet on each ISP.

Is it the correct configuration ?

1 shared VIP from ISP 1 + 4 IP (2 for WAN1 MX1 + 2 for WAN1 MX2).

1 shared VIP from ISP 2 + 4 IP (2 for WAN2 MX1 + 2 for WAN2 MX2).

Many thanks.

[Mloraditch]

Each MX will only need 1 IP for each ISP and then the shared VIP IP between both.

[CedricMX]

Hi,

Finally, from my understanding :

- for the 2 MX i will need 3 public IP address.

- for the ISP 1 router i will need 2 public IP address

In conclusion, ISP 1 must provide a total of 5 public ip address.

Correct ?

Many thanks

[prabhulkars]

Hello,

Per ISP you would need 4 IPs:
1 for MX 1 WAN
1 for MX 2 WAN
1 for the Gateway for both
1 for the shared VIP

Hope this helps!

[CedricMX]

so a /29 subnet would be great.

@prabhulkars For VRRP, do you suggest using LAN side ? Each MX will be connected to the LAN switch ?

Many thanks

[cmr]

The HA is automatic and does use the LAN side.  So yes, each MX needs to connect to the same LAN (or VLAN).

[prabhulkars]

Yes, /29 would work for you.
VRRP is by default sent over LAN and it uses the LAN VLANs for VRRP traffic. Please check the following documentation on more details regarding High Availability pair:

https://documentation.meraki.com/MX/Deployment_Guides/MX_Warm_Spare_-_High_Availability_Pair