If you want to control traffic between VNICs in a particular NSG, you can also write rules that specify the rule`s NSG as the source (for inbound rules) or destination (for outbound rules). Sounds like you all need to simplify. Some limits are not increased if they cause performance changes on the backend that affect the customer experience. In addition, AWS certainly does not approve all requests, especially beyond the strict limits. It depends on the service, but the more the service is managed, the less flexibility you have. A packet in question is allowed if a rule in one of the relevant lists and groups allows traffic (or if the traffic is part of an existing tracked connection). There is a caveat if the lists contain both stateful and stateless rules that cover the same traffic. For more information, see Stateful Rules and Stateless Rules. Unfortunately, it seems that I have exceeded the maximum limit of security group rules. What options do I have? Is running your own firewall the only solution? To use an NSG, add the desired VNICs to the group.
Typically, however, when you add a virtual network adapter to the group, you are working with the parent resource, not with the virtual network adapter itself. For example, if you create a compute instance, you can optionally specify a network security group for the instance. Although you conceptually include the instance in the group, you actually place the instance`s primary virtual network adapter in the NSG. The group`s security rules apply to this VNIC, not the instance. When you add a secondary virtual network adapter to the instance, you can optionally specify a network security group for that network adapter, and the rules apply to that virtual network adapter and not to the instance. Note that all VNICs in a particular NSG must reside in the PNT to which the NSG belongs. A quota change applies to both incoming and outgoing rules. This quota multiplied by the security group quota per network interface cannot exceed 1,000. However, you can use security lists and network security groups together if necessary. For more information, see If you use both security lists and network security groups. Oracle recommends using network security groups instead of security lists because they allow you to separate the subnet architecture of the VCN from the security needs of your applications.
If for some reason you are using both stateful and stateless rules, and there is traffic that matches both a stateful rule and a stateless rule in a particular direction (for example, inbound), the stateless rule takes precedence and the connection is not tracked. You need an appropriate rule in the other direction (for example, outbound, stateless, or stateful) to allow response traffic. Security groups are applied to an instance`s network interface. By default, AWS allows you to apply up to five security groups to a virtual network interface, but you can use even more in extreme situations (the cap is 16). To do this, you must contact AWS Support. Of course, you are free to use the default security group, but most administrators create custom VPC security groups to override or extend the default group. However, before creating security groups, it is important to understand some applicable limits. The following Maximum Transmission Unit (MTU) rules apply to traffic passing through a VPC endpoint. Your instances running platform images also have operating system firewall rules that control access to the instance.
When you troubleshoot access to an instance, make sure that all of the following are set correctly: Also note that instances in a VPC are not allowed to communicate with each other unless you specifically allow it. The default security group allows communication between instances, but if you do not want to use the default security group, you must create rules that allow the desired communication between instances. Security lists allow you to define a set of security rules that apply to all network networks in an entire subnet. To use a specific security list with a specific subnet, associate the security list with the subnet when you create the subnet or later. A subnet can be assigned to up to five security lists. All network adapters created on this subnet are subject to the security lists associated with the subnet. Figure 1 shows an example of a security group. As you can see in the figure, each security group contains a collection of inbound and outbound rules. Security group rules are used to grant permissions to a specific type of traffic. There is no deny rule, because traffic is denied unless there is a rule that allows it. The exception is that response traffic is allowed.
For example, if an instance sends a request, the response to that request is allowed to enter the instance, even if security rules would otherwise have blocked that type of communication. A given virtual network adapter can have a maximum of 5 NSGs.* 07 If the total number of inbound and outbound rules identified in steps 5 and 6 is greater than 50, the selected Amazon EC2 security group exceeds the recommended threshold for the number of defined rules. Therefore, you must take action and remove any unnecessary or overlapping inbound and outbound rules to restore the performance efficiency of the resource or resources. of the selected security group. The VCN`s default security list contains several default rules, but none to allow ping. If you want to ping an instance, ensure that the instance`s applicable security lists or network security groups include an additional stateful entry rule to specifically allow ICMP type 8 traffic from the source network from which you want to ping.
