The TCP flags from the offending frame.
The flags are: S (SYN), F (FIN), R (RESET), P (PUSH), A (ACK), U (URGENT),
4 (low-order unused bit), 8 (high-order unused bit)
options
The TCP options from the offending frame.
The options are displayed as "option-value", separated by commas. No-ops are
not displayed