A capsule socket of a filling machine for two-piece capsules and a socket system having such a capsule socket and a capsule half of a two-piece capsule are disclosed herein. The two-piece capsules have two capsule halves, each with a capsule base and a capsule wall. The capsule socket includes a main body having a receiving space for the capsule half formed therein. The receiving space has a base portion, assigned to the respective capsule base, and a circumferential wall portion for centering the capsule wall. The receiving space has a clamping portion between the base portion and the circumferential wall portion. The clamping portion has a smaller free cross section than the circumferential wall portion. In the transition region from its base to its wall, the capsule half has a capsule part diameter. The clamping portion has a free clamping diameter, which is smaller than the capsule part diameter.
