> For the complete Linea documentation index, see [llms.txt](/llms.txt). > Agents can fetch this page as Markdown at [https://docs.linea.build/api/linea-smart-contracts/messageservice/messageservicebase.md](https://docs.linea.build/api/linea-smart-contracts/messageservice/messageservicebase.md). # MessageServiceBase # `MessageServiceBase` ### messageService ```solidity contract IMessageService messageService ``` The message service address on the current chain. ### remoteSender ```solidity address remoteSender ``` The token bridge on the alternate/remote chain. ### RemoteSenderSet ```solidity event RemoteSenderSet(address remoteSender, address setter) ``` _Event emitted when the remote sender is set._ #### Parameters | Name | Type | Description | | --- | --- | --- | | remoteSender | address | The address of the new remote sender. | | setter | address | The address of the account that set the remote sender. | ### CallerIsNotMessageService ```solidity error CallerIsNotMessageService() ``` _Thrown when the caller address is not the message service address_ ### SenderNotAuthorized ```solidity error SenderNotAuthorized() ``` _Thrown when remote sender address is not authorized._ ### onlyMessagingService ```solidity modifier onlyMessagingService() ``` Requirements: - The msg.sender must be the message service._ ### onlyAuthorizedRemoteSender ```solidity modifier onlyAuthorizedRemoteSender() ``` Requirements: - The original message sender via the message service must be a known sender._ ### __MessageServiceBase_init ```solidity function __MessageServiceBase_init(address _messageService) internal ``` Initializes the message service _Must be initialized in the initialize function of the main contract or constructor._ #### Parameters | Name | Type | Description | | --- | --- | --- | | _messageService | address | The message service address, cannot be empty. | ### _setRemoteSender ```solidity function _setRemoteSender(address _remoteSender) internal ``` Sets the remote sender _This function sets the remote sender address and emits the RemoteSenderSet event._ #### Parameters | Name | Type | Description | | --- | --- | --- | | _remoteSender | address | The authorized remote sender address, cannot be empty. | Contributions not accepted These reference pages are automatically generated based on Linea's [smart contracts](https://github.com/Consensys/linea-monorepo/tree/main/contracts/src). To ensure they accurately match the deployed smart contracts, we cannot accept any contributions that edit these pages.