<p>The security window on Cardano is defined as 3k/f, where 10k/f is epoch length. The security window is the farthest one can rollback under normal circumstances. On mainnet this is 36 hours.</p>

CC BY-SA 4.0
2022-04-06T03:26:46.420Z
thank you! 

reference found: https://docs.cardano.org/core-concepts/chain-confirmation-versus-transaction-confirmation
Myles
CC BY-SA 4.0
2022-04-06T03:15:07.277Z
2022-04-06T03:15:07.277Z
Samuel Leathers
<p>Where can you check the maximum allowable length of a chain fork for the current era? And past/future eras?</p>

<cardano-node>
Maximum allowable length of a chain fork
# Maximum allowable length of a chain fork

(Asked by: username_0 on 2022-04-06)

Where can you check the maximum allowable length of a chain fork for the current era? And past/future eras?

**Tags:** cardano-node

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## 1 answers

### Answer by username_1 on 2022-04-06. Score: 3

The security window on Cardano is defined as 3k/f, where 10k/f is epoch length. The security window is the farthest one can rollback under normal circumstances. On mainnet this is 36 hours.

> **Comments:**
> **username_0**: thank you!   reference found: https://docs.cardano.org/core-concepts/chain-confirmation-versus-transaction-confirmation  

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