Header « Back to Glossary IndexA header is the extra information in a packet that is needed for the protocol stack to process the packet. Related Articles: Glossary: Tiny Fragment AttackGlossary: TCP FingerprintingGlossary: Stateful InspectionGlossary: Packet SniffingGlossary: Fragment Overlap AttackHeader (Wikipedia)Look up header in Wiktionary, the free dictionary.Header may refer to: