# Incident Summary: 2023-09-07

DevFeed: [Incident Summary: 2023-09-07](<https://devfeed.tech/articles/incident-summary-2023-09-07-15692.md>)

Original publisher: [Read original article](<https://developer.squareup.com/blog/incident-summary-2023-09-07>)

Author: Square Engineering

Published: 2023-09-15T23:00:00Z

Content type: article

Language: en

Sources: [Square Corner Blog RSS Feed](<https://devfeed.tech/sources/square-corner-blog-rss-feed.md>)

Topics: [incident](<https://devfeed.tech/topics/incident.md>), [Firewall](<https://devfeed.tech/topics/firewall.md>), [networking](<https://devfeed.tech/topics/networking.md>), [datacenter](<https://devfeed.tech/topics/datacenter.md>), [Microservice](<https://devfeed.tech/topics/microservice.md>), [systems](<https://devfeed.tech/topics/systems.md>)

Tags: [analysis](<https://devfeed.tech/tags/analysis.md>), [datacenters](<https://devfeed.tech/tags/datacenters.md>), [engineering](<https://devfeed.tech/tags/engineering.md>), [firewall](<https://devfeed.tech/tags/firewall.md>), [incident](<https://devfeed.tech/tags/incident.md>), [infrastructure](<https://devfeed.tech/tags/infrastructure.md>), [microservices](<https://devfeed.tech/tags/microservices.md>), [outage](<https://devfeed.tech/tags/outage.md>), [root-cause-analysis](<https://devfeed.tech/tags/root-cause-analysis.md>), [routing](<https://devfeed.tech/tags/routing.md>), [systems](<https://devfeed.tech/tags/systems.md>)

## AI overview

Square describes a multi-hour outage beginning on September 7, 2023. The incident was caused by a host-based firewall change and a DNS service upgrade that together created unexpected load on internal DNS servers, leading services to lose communication with dependencies. The article provides a timeline, root-cause overview, and remediation steps.

## Source excerpt

A timeline of the events of the outage and steps for remediation