I am really not clear what outbound(egress) and inbound(ingress) traffic means. I have two theories
inbound just specifies that the origin is outside and target inside i.e. HTTP round trip to some VM hosted web is ingress, the response with HTTP 200 status goes the same established route back
inbound is anything from internet and outbound is anything to internet. So HTTP roundtrip to azure VM is ingress and also egress (HTTP response), both of which can have different route(in case of asymmetric routing.
My question is if the VM does not have route back to internet, will it serve properly the HTTP or the response cannot reach the originator in internet?