proxmox/docs/07-ccip/CCIP_BRIDGE_MAINNET_CONNECTION.md

CCIP Bridge ↔ Ethereum Mainnet Connection

Last Updated: 2026-02-12
Status: Active

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Overview

Chain 138 does not use Chainlink’s public CCIP network (custom chain). Cross-chain sends from Chain 138 to Ethereum mainnet use:

1. Chain 138: Custom router + WETH9 bridge (emits MessageSent).
2. Mainnet: Deployed CCIPRelayRouter and CCIPRelayBridge that accept relayed messages.
3. Relay service: Off-chain process that watches Chain 138 for MessageSent and calls mainnet relay router to deliver.

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Mainnet Contracts (Ethereum)

Contract	Address	Role
CCIPRelayRouter	0xAd9A228CcEB4cbB612cD165FFB72fE090ff10Afb	Receives relayed messages; calls bridge ccipReceive. Relayer must have RELAYER_ROLE.
CCIPRelayBridge	0xF9A32F37099c582D28b4dE7Fca6eaC1e5259f939	Holds WETH; releases to recipient when relay router calls ccipReceive. Must be funded with WETH for payouts.
WETH9	0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2	Canonical mainnet WETH.

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Chain 138 Setup

Role	Address	Notes
Router (LINK fee)	0x42DAb7b888Dd382bD5Adcf9E038dBF1fD03b4817	Emits MessageSent; relay service listens here.
Bridge (LINK fee)	0xcacfd227A040002e49e2e01626363071324f820a	Pay fee in Chain 138 LINK. Default in CCIPWETH9_BRIDGE_CHAIN138.
Bridge (native ETH fee)	0x63cbeE010D64ab7F1760ad84482D6cC380435ab5	Pay fee in native ETH.

Both bridges have mainnet destination set to CCIPRelayBridge (0xF9A32F37099c582D28b4dE7Fca6eaC1e5259f939), so all 138→mainnet sends are delivered via the relay.

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End-to-End Flow

1. User on Chain 138 calls bridge sendCrossChain(mainnetSelector, recipient, amount) (e.g. via scripts/bridge/run-send-cross-chain.sh).
2. Bridge pulls WETH from user, calls router ccipSend(...) with receiver = abi.encode(CCIPRelayBridge).
3. Router emits MessageSent (no Chainlink relayer).
4. Relay service (Node) watches the Chain 138 router for MessageSent, builds Any2EVMMessage, and calls mainnet CCIPRelayRouter.relayMessage(CCIPRelayBridge, message).
5. Relay router calls CCIPRelayBridge.ccipReceive(message); bridge transfers WETH to recipient on mainnet.

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Running the Relay Service

1. Fund mainnet CCIPRelayBridge with WETH so it can pay recipients:

   # Option A: Script (transfers deployer's full WETH balance by default)
   ./scripts/bridge/fund-mainnet-relay-bridge.sh
   # Option B: Specific amount (wei)
   ./scripts/bridge/fund-mainnet-relay-bridge.sh 1000000000000000000
   
   # Or manually:
   cast send 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 \
     "transfer(address,uint256)" \
     0xF9A32F37099c582D28b4dE7Fca6eaC1e5259f939 \
     <amount_wei> \
     --rpc-url $ETHEREUM_MAINNET_RPC --private-key $PRIVATE_KEY --legacy
   

   If the default RPC rate-limits (429), set ETHEREUM_MAINNET_RPC to Infura or Alchemy in smom-dbis-138/.env.

2. Grant relayer role (if not already): The relay tx will revert with "transaction execution reverted" (no revert data) until the relayer address has RELAYER_ROLE on the mainnet router. As the router's admin (deployer), run:

   ./scripts/bridge/grant-relayer-role-mainnet.sh
   

   Or manually: cast send 0xAd9A228CcEB4cbB612cD165FFB72fE090ff10Afb "grantRelayerRole(address)" 0x4A666F96fC8764181194447A7dFdb7d471b301C8 --rpc-url $ETHEREUM_MAINNET_RPC --private-key $PRIVATE_KEY --legacy

3. Start the relay service:

   cd smom-dbis-138/services/relay
   # .env: RPC_URL_138, RPC_URL_MAINNET or ETHEREUM_MAINNET_RPC (Infura/Alchemy recommended to avoid 429), PRIVATE_KEY (relayer), CCIP_RELAY_*
   npm start
   

   For mainnet RPC, set RPC_URL_MAINNET in services/relay/.env or ETHEREUM_MAINNET_RPC in smom-dbis-138/.env. Prefer Infura (https://mainnet.infura.io/v3/<PROJECT_ID>) or Alchemy; see RPC_ENDPOINTS_MASTER.md.

Config defaults in services/relay/src/config.js point to the router and bridges above; override with env vars if needed.

If relay tx reverts with "transaction execution reverted"

1. Relayer role: Ensure the relayer has RELAYER_ROLE: run ./scripts/bridge/grant-relayer-role-mainnet.sh (use RPC_URL_MAINNET=https://ethereum.publicnode.com if Infura returns 403).
2. Bridge WETH: The mainnet CCIPRelayBridge must hold at least the amount being relayed. If the bridge balance is lower than the transfer amount, fund it:

   RPC_URL_MAINNET=https://ethereum.publicnode.com ./scripts/bridge/fund-mainnet-relay-bridge.sh 1000000000000000
   

   (1e15 wei = 0.001 WETH.)

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References

• SEND_ETH_TO_MAINNET_REVERT_TRACE.md — Revert history and deployed LINK/native-ETH bridges.
• scripts/README.md §8 — Send command and env.
• services/relay/README.md — Relay service deployment and config.
• CONTRACT_ADDRESSES_REFERENCE.md — Chain 138 addresses.