When an NSG is created, it contains a set of default rules that completely shut down the inbound and outbound traffic:
Figure 3.25 – Default security rules
The current setup can be read as follows:
- It allows for any inbound traffic that originates in the VNet and ends in the VNet (see the SOURCE and DESTINATION columns).
- It allows for any inbound traffic that accesses a load balancer first (see the SOURCE column).
- It denies any traffic that does not fulfill the preceding inbound rules (the lowest priority rule—65500).
- It allows for outbound traffic inside the network.
- It allows any resource in the VNet to access the internet (see DESTINATION column).
- It denies any outbound traffic that does not meet the preceding outbound rules (the lowest priority rule—65500).
You should see the preceding result when you access your NSG in the portal. In fact, a similar result is displayed when creating a security group via the CLI:
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