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[Support] Apply 499 and origin timeout review replacements #34060

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[Support] Apply 499 and origin timeout review replacements #34060

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53180bb
[Support] Clarify 499 and origin connection timeout guidance
dpolaske-cloudflare Oct 6, 2026
b44e81b
[Support] Apply 522 resolution review feedback
dpolaske-cloudflare Oct 7, 2026
3d9a42a
[Support] Address remaining 499 and 522 review feedback
dpolaske-cloudflare Oct 8, 2026
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12 changes: 10 additions & 2 deletions src/content/docs/fundamentals/reference/connection-limits.mdx
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Expand Up @@ -19,15 +19,23 @@ When HTTP/HTTPS traffic is [proxied through Cloudflare](/fundamentals/concepts/h

## Between Cloudflare and origin server

### What connection means here

A **TCP connection** is established when its TCP handshake completes. For a new **TCP-based HTTPS connection**, setup also requires SSL/TLS negotiation. TCP can therefore be established while HTTPS setup remains unfinished.

Requests can reuse established connections, and a proxied request may traverse multiple connections. A connection timeout does not, by itself, identify which operation timed out or what caused it. Reused connections and QUIC do not have the same per-request TCP/TLS setup sequence as a new TCP-based HTTPS connection.

The TCP establishment and request-acknowledgment rows describe specific TCP timeout conditions. They are not an exhaustive list of every operation that can produce [522](/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-522/). Neither value is a universal TCP-plus-TLS setup budget. A timeout while TLS remains pending can be reported as `522` rather than [525](/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-525/).

:::note

If you are using [Cloudflare tunnels](/cloudflare-one/networks/connectors/cloudflare-tunnel/), refer to [Origin configuration](/cloudflare-one/networks/connectors/cloudflare-tunnel/configure-tunnels/origin-parameters/) to view or modify your connection settings.
:::

| Type | Limit (seconds) | HTTP status code at limit | [Configurable](/fundamentals/reference/connection-limits/#configurable-limits) |
| ----------------------------------------------------------------------------------------- | --------------- | -------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------ |
| <GlossaryTooltip term="TCP three-way handshake">Complete TCP Connection</GlossaryTooltip> | 19 | [522](/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-522/) | No |
| <GlossaryTooltip term="ACK (Acknowledge)">TCP ACK</GlossaryTooltip> Timeout | 90 | [522](/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-522/) | No |
| <GlossaryTooltip term="TCP three-way handshake">TCP connection establishment</GlossaryTooltip> | 19 | [522](/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-522/) | No |
| <GlossaryTooltip term="ACK (Acknowledge)">TCP request acknowledgment</GlossaryTooltip> timeout | 90 | [522](/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-522/) | No |
| <GlossaryTooltip term="TCP Keep-Alive">TCP Keep-Alive</GlossaryTooltip> Interval | 30 | [520](/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-520/) | No |
| <GlossaryTooltip term="idle connection">Proxy Idle</GlossaryTooltip> Timeout | 900 | [520](/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-520/) | No |
| <GlossaryTooltip term="proxy read timeout">Proxy Read Timeout</GlossaryTooltip> | 125 | [524](/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-524/) | [Yes, for Enterprise zones](/api/resources/zones/subresources/settings/methods/edit/) |
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