Hello Faiz,
As you probably know, NetFlow by default is only collected ingress. The ingress flows collected on all interfaces are used to display the outbound traffic on a selected interface. I don't know about ManageEngine but, in some NetFlow solutions, interfaces without NetFlow/IPFIX enabled will not be displayed regardless of whethor or not flows are going out of it.
Regarding ingress/egress being enabled on the same interface. If you are using flexible NetFlow to configure the export, make sure the "flow direction" is exported in the template. The commands to export both look like this:
ip flow monitor andrew-mon input
ip flow monitor andrew-mon output
Here is a good article on enabling ingress and egress NetFlow. Realize that just because you export both ingress and egress on a single interface and you export the direction, this doesn't mean the NetFlow solution will report on the data with a behavior that you would expect.
Ingress and egress flows are exported at the same time with only one difference "flow direction". For this reason, this element must be included in the template to ensure that utilization isn't overstated in the flow report. Again, this of course depends on your reporting solution.
Many vendors can't deal with a mixture of ingress and egress flows being enabled in a seemingly random fashion on the same device. In other words, they expect all ingress or all egress. Only a few vendors can handle a hybrid approach.
I hope this helps.
Jake
