<p>The replica could not validate the binary log event checksum while reading over the network, so replication stops.</p>
<p>MySQL Error 1743: ER_NETWORK_READ_EVENT_CHECKSUM_FAILURE happens when a replica reads a binary log event whose checksum does not match, indicating network corruption or mismatched settings. Verify CRC32 checksums, align binlog_checksum and master_verify_checksum, and restart replication with a fresh position to resolve the issue.</p>
Replication event checksum verification failed while
Error 1743 is raised by MySQL when a replication slave (replica) receives a binary log event whose checksum does not match the CRC32 value sent by the source (master). MySQL aborts replication to prevent applying corrupted data.
The error text is: Replication event checksum verification failed while reading from network. It appears in the replica's error log or SHOW SLAVE STATUS Last_SQL_Error field.
The failure surfaces immediately after the replica requests events from the master or relay log that include checksums. It can happen during initial cloning, after CHANGE MASTER TO, or during continuous replication.
Because the checksum is validated per event, the first corrupted or improperly formatted event stops SQL thread execution, halting replication until the fault is corrected.
A stopped replica no longer applies updates, so downstream reads become stale and failover strategies break. Ignoring the error risks data inconsistency, delayed recovery, and longer outages.
Network packet corruption between master and replica, often due to flaky VPN links or overloaded NICs, alters the binary log payload and invalidates the checksum.
Mismatched binlog_checksum settings: if the master writes events with CRC32 but the replica expects NONE, the checksum length is misread and verification fails.
Changes to master_verify_checksum or slave_sql_verify_checksum options without restarting replication cause inconsistent verification logic.
Disk corruption in relay logs where a damaged event checksum no longer matches the stored CRC32.
Error 1593 - ER_SLAVE_FATAL_ERROR_RUNNING_QUERY: replication stops due to a SQL execution failure rather than checksum mismatch.
Error 1236 - ER_MASTER_FATAL_ERROR_READING_BINLOG: the replica cannot read the master binary log, often due to file deletion or corruption.
Error 1032 - ER_KEY_NOT_FOUND: a row expected during replication delete/update is missing, causing replication stop.
Error 1872 - ER_SLAVE_RELAY_LOG_READ_FAILURE: relay log corrupted on disk, preventing further event processing.
No. While network corruption is common, mismatched replication checksum settings or relay log disk damage can also trigger the error.
Disabling checksums (binlog_checksum=NONE) hides the symptom but risks silent data corruption. Align settings instead of disabling.
Galaxy's query editor surfaces replication lag metrics and error logs in real time, letting engineers detect ER_NETWORK_READ_EVENT_CHECKSUM_FAILURE quickly and trigger automated playbooks.
If the corrupted event never reaches the replica intact, reinitializing from a fresh snapshot ensures no missing transactions.
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