Symptoms

Packets from an iRule that uses the [drop] command pass through to the other side of the connection.

Impact

For stateless/message-based protocols (UDP, SIP), or given a mid-connection call to drop (HTTP_REQUEST, for example), this passes data before tearing down the protocol control block. Depending on the application, this can be dangerous. In the case of a stateful protocol (TCP, SCTP) using the drop command in CLIENT_ACCEPTED, the next segment will result in a RST packet or ABORT chunk, so there is less impact.

Conditions

An iRule calls drop.

Workaround

None.

Fix Information

Add a temporary flag to note that the connection has been asynchronously aborted, and avoid delivering the packet when this is set.

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips