[General] <Can I use the Holesky testnet connect the Op Sepolia testnet??>

[Guan21]

Discussion Topic

Hello developers,
Does anyone know the L1CrossDomainMessenger address on the Holesky testnet?
I need to send a message from Holesky testnet to OP Sepolia testnet.
I tried using this address: 0x81C4Bd600793EBd1C0323604E1F455fE50A951F8
However, it cannot send messages because I received this error:

Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending? 

execution reverted

Do you hava any Idea to fix it.

[Guan21]

I deployed the same contract to L1 Sepolia and L1 Holesky.
The Sepolia one worked normal.
But the Holesky one got the error.

[opfocus]

You can't send a message from Holesky testnet to OP Sepolia testnet. if you care about interoperability, you can read https://docs.optimism.io/stack/interop/tools/devnet

[jsvisa]

Does anyone know the L1CrossDomainMessenger address on the Holesky testnet?

From the op document, seems they only maintain the mainnet and sepolia, so no holesky contracts were deployed by the team at the moment.

For this address https://holesky.etherscan.io/address/0xdDD8d52436773e99B4C363724Eb0d40929FA15F8

1. this address is the L1CrossDomainMessenger implementation address, for the end users, they should use the proxy address instead
2. If you find the proxy address, I'm not sure this is the correct L1CrossDomainMessenger or not

[Guan21]

@jsvisa
Thanks for your comment.
I found it and tried to use it, but it had no effect. Then I found this address https://holesky.etherscan.io/address/0x01c7b17AbA8F7aaeE339a5422845aafAd20AB4e8#events. It seems promising, but I still haven't received the message in the L2 contract.

For the details

I have those contracts.

---

(Holesky)L1CrossDomainMessenger: 0x01c7b17AbA8F7aaeE339a5422845aafAd20AB4e8
(Op Sepolia)L2CrossDoaminMessager: 0x4200000000000000000000000000000000000007
(Holesky)L1StandardBridgeContract: 0x0d6f85ca8c738c8ae7e02cedb6b278cd7dd86098
(Op Sepolia)L2StandardBridgeContract: 0xf8cb9554c8824C30D061634069bB55F49483836a

---

Step1 : I connect my L1StandardBridge Contract to (L1CrossDomainMessenger) 0x01c7b17AbA8F7aaeE339a5422845aafAd20AB4e8.

Step2: I send the message to L2. The event logs is blow
https://holesky.etherscan.io/tx/0xf593adb3ed6d060b3f2994ea7bb87fe0286994d87de2563b2c354783fcb216ac#eventlog
It seems good.

Then Call SentMessageExtension1 L1CrossDomainMessenger event

And I saw this.
0x12d8b17aBa8F7aAEE339A5422845AAfAD20Ac5F9 need to relay the message to L2CrossDoaminMessager
but there nothing in 0x12d8b17aBa8F7aAEE339A5422845AAfAD20Ac5F9

Question

• Why 0x12d8b17aBa8F7aAEE339A5422845AAfAD20Ac5F9 did not relay message to L2CrossDoaminMessager?

[jsvisa]

@Guan21 thanks for the explain, but I have some questions?

And I saw this.
0x12d8b17aBa8F7aAEE339A5422845AAfAD20Ac5F9 need to relay the message to L2CrossDoaminMessager
but there nothing in 0x12d8b17aBa8F7aAEE339A5422845AAfAD20Ac5F9

Why do you think 0x12d8b17aBa8F7aAEE339A5422845AAfAD20Ac5F9 should relay the message?

And as you sent the message on holesky, why did this message need to be relayed to op-sepolia, shouldn't it be op-holesky(if any)?

[Guan21]

@jsvisa
Sepolia is an Ethereum testnet that can send messages to OP-Sepolia. Similarly, Holesky is another Ethereum testnet that should also be able to send messages to OP-Sepolia.

Based on your comment, OP-Sepolia doesn't have a relayer server for the Holesky testnet. This means I cannot send messages from Holesky to OP-Sepolia, correct?

[opfocus]

Sepolia is the data layer of op-seplolia, Holesky is not.
L2 chain derivation — deriving L2 blocks from L1 data — is one of the main responsibilities of the rollup node, both in validator mode, and in sequencer mode (where derivation acts as a sanity check on sequencing, and enables detecting L1 chain re-organizations).
L2 Chain Derivation Specification