How to configure IP for each NIC

Configuring synchronization, sensors, and optimizations
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How to configure IP for each NIC

Post by CRM User » Wed Mar 13, 2019 12:47 pm

I have setup my 2 PBX nodes (each with 2 NIC's) with IP addresses as follows:

PBX1:
- NIC 1 (management): IP 192.168.1.5, subnet 255.255.255.0
- NIC 2 (VoIP): IP 192.168.1.100, subnet 255.255.255.0

PBX2:
- NIC 1 (management): IP 192.168.1.6, subnet 255.255.255.0
- NIC 2 (VoIP): IP 192.168.1.100, subnet 255.255.255.0

Traffic never seems to work on the VoIP NICs, and if I bring up and down the Management NICs then sometimes VoIP traffic flows but the nodes can find each other (management IPs). I have told HAAst to control the VoIP IP (192.168.1.100) and I see the IP move between nodes, but it still doesn't work overall.

What is going on with HAAst?

Note from Telium: The same issue you are describing can also cause another symptom, where VoIP packets leaving the node appear to be coming from the wrong IP address or wrong NIC. The root cause is the same however, and the solution (below) is the same
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Re: Network or IP problems

Post by Telium Support » Wed Mar 13, 2019 12:52 pm

The problem you are encountering has nothing to do with HAAst, and everything to do with the basics of networking. You have setup 2 NIC's in each PC, but they are on the same subnet! That means that Linux has no idea where (out which NIC) to route traffic for your 192.168.1.0/24 subnet. You should not do this as it confuses Linux. This topic is part of what's known as "multihoming", and I would suggest you research this topic a bit further before you continue to setup your networks. As well, reread the HAAst installation guide - there's a bit more information on this topic there. (This isn't the first time we've seen this issue in the support group).

By shutting down NIC1 on either PC you allow Linux to figure out how to properly route, but then your management NIC is gone so the cluster fails over.

The solution (for 2 NIC's per PBX) is to ensure that each NIC is on it's own subnet. For example:
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Telium Support
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Re: Network or IP problems

Post by Telium Support » Wed Mar 13, 2019 1:08 pm

Please note that it IS possible to setup HAAst with only a single NIC and single IP per server. However, you would have to disable the HAAst 'VoIPNIC' feature and use only a single IP for management and VoIP traffic (plus use event handlers to modify settings), or use a single NIC with a virtual NIC on a VLAN.

Note: Most companies prefer to keep VoIP traffic on a separate subnet from management traffic for QoS/DSCP reasons.
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