Postage stamps must be produced by the post administration of a corresponding country or by authorized philatelic agents. If an agency has no contract with the post administration of a corresponding country or violate the agreement it has signed, the agency has no right to produce postage stamps.

Themes, designs, denomination, release date, edition and other important stages in stamp production are decided together between the agent and the concerned post administration. Philatelic agent is responsible for the quality of the stamps. It is not easy to detect if a postage stamp is legal because it concerns the official agreement between a post administration and an agency to be its representative. Postage stamps produced without this agreement are illegal and have no value.

Illegal postage stamps cause much harm to the philatelic trade and stamp collectors. To ensure fair trade and legal production of postage stamps, it is necessary for all the philately admirers and retailers to cooperate.

The descriptions of legal stamp issues usually appear in the official websites and stamp catalogues of the authorized philatelic agents: Scott (USA), Yvert and Tellier (France), Michel (Germany). The lists of postage stamps are also frequently found in many philatelic periodicals.

Fake stamps ≠ illegal stamps.

Illegal stamps can be also determined as “bogus stamps” or “unofficial stamps”. Less correct but similar names are “cinderella stamps”, “phantasy stamps”, etc. Illegal stamps and fake stamps should not be considered as synonyms because they have different meanings.

“Fake stamps” equally often called “counterfeit stamps”, are the illegal copies of official stamps – such activity is a criminal offence in many countries. Most likely a person who is interested in producing fake stamps would try to create highly similar copies of official postage stamps and sell them as originals.

Illegal stamps are private newly created labels that imitate usual forms, paper and other features of postage stamps. Usually their producer simulates to have relations with a post administration whose name he/she is illegitimately using.

The production of illegal postage stamps is against the law as it breaches the rights of a post administration and harms the activity of stamp collectors (except the cases when the collector is informed that the stamps are illegal).