← All articles

#dns

DNS in AWS — the VPC resolver, its per-interface packet limit, and why hitting that limit looks like random SERVFAIL and five-second application timeouts.

1 article tagged #dns, newest first.

August 21, 2026
The VPC DNS Limit: 1,024 Packets per Second per ENI
The VPC resolver caps every network interface at 1,024 DNS packets per second. It is not adjustable, has no CloudWatch metric, and looks like random SERVFAIL.