# Validation Rules While Cero network does not maintain the state tree of all the Rollup subscribed to it, its still important for it to validate the transactions before they are preconfirmed or added to the batches. The reasoning behind this is pretty straight, the transaction order once confirmed by the Cero chain should be absolute and Rollups cannot drop the transactions at will once confirmed by Cero chain. These checks include the following, 1. London Fork - Before London fork, only allow legacy transactions. If London fork is enabled, then allow EIP1559. 2. EIP155 - Only allow transactions with EIP155 enabled. 3. Min Gas Price Check - Only accept transactions with minimum gas price set to the Rollup's configured value. 4. Rollup's Registration Check - Ensure the transactions for sequencing are corresponding to a registered Rollup. 5. Max Gas Limit - Gas limit inside a Rollup. 6. Max Transaction Fee - Maximum transaction acceptable in a transcation. 7. Balance Checks - If an account has sufficient balance to cover for fees for the time of execution on Rollup's side. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.cero.network/concepts/validation-rules.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.