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# Callbacks
Application modules implementing the IBC module must implement the following callbacks as found in [05-port](../05-port/types/module.go).
```go
// IBCModule defines an interface that implements all the callbacks
// that modules must define as specified in ICS-26
type IBCModule interface {
OnChanOpenInit(
ctx sdk.Context,
order channeltypes.Order,
connectionHops []string,
portID string,
channelID string,
channelCap *capability.Capability,
counterParty channeltypes.Counterparty,
version string,
) error
OnChanOpenTry(
portID,
counterparty channeltypes.Counterparty,
version,
counterpartyVersion string,
OnChanOpenAck(
OnChanOpenConfirm(
OnChanCloseInit(
OnChanCloseConfirm(
// OnRecvPacket must return the acknowledgement bytes
OnRecvPacket(
packet channeltypes.Packet,
) (*sdk.Result, []byte, error)
OnAcknowledgementPacket(
acknowledgement []byte,
) (*sdk.Result, error)
OnTimeoutPacket(
}
```