Default network ACL - Amazon Virtual Private Cloud
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Default network ACL

The default network ACL is configured to allow all traffic to flow in and out of the subnets with which it is associated. Each network ACL also includes a rule whose rule number is an asterisk (*). This rule ensures that if a packet doesn't match any of the other numbered rules, it's denied. You can't modify or remove this rule.

The following is an example default network ACL for a VPC that supports IPv4 only.

Inbound
Rule # Type Protocol Port range Source Allow/Deny

100

All IPv4 traffic

All

All

0.0.0.0/0

ALLOW

*

All IPv4 traffic

All

All

0.0.0.0/0

DENY

Outbound
Rule # Type Protocol Port range Destination Allow/Deny

100

All IPv4 traffic

All

All

0.0.0.0/0

ALLOW

*

All IPv4 traffic

All

All

0.0.0.0/0

DENY

If you create a VPC with an IPv6 CIDR block or if you associate an IPv6 CIDR block with your existing VPC, we automatically add rules that allow all IPv6 traffic to flow in and out of your subnet. We also add rules whose rule numbers are an asterisk that ensures that a packet is denied if it doesn't match any of the other numbered rules. You can't modify or remove these rules. The following is an example default network ACL for a VPC that supports IPv4 and IPv6.

Note

If you've modified the inbound rules of your default network ACL, we do not automatically add an ALLOW rule for inbound IPv6 traffic when you associate an IPv6 block with your VPC. Similarly, if you've modified the outbound rules, we do not automatically add an ALLOW rule for outbound IPv6 traffic.

Inbound
Rule # Type Protocol Port range Source Allow/Deny

100

All IPv4 traffic

All

All

0.0.0.0/0

ALLOW

101

All IPv6 traffic

All

All

::/0

ALLOW

*

All traffic

All

All

0.0.0.0/0

DENY

*

All IPv6 traffic

All

All

::/0

DENY

Outbound
Rule # Type Protocol Port range Destination Allow/Deny

100

All traffic

All

All

0.0.0.0/0

ALLOW

101

All IPv6 traffic

All

All

::/0

ALLOW

*

All traffic

All

All

0.0.0.0/0

DENY

*

All IPv6 traffic

All

All

::/0

DENY