I am trying to experiment with mev-boost on goerli testnet but I am getting connection error in my beacon node log.

MEV boost command:

sudo docker run flashbots/mev-boost -goerli  -relay-check -relays=https://0xafa4c6985aa049fb79dd37010438cfebeb0f2bd42b115b89dd678dab0670c1de38da0c4e9138c9290a398ecd9a0b3110@builder-relay-goerli.flashbots.net

Here are my logs:

time="2022-09-16T10:29:57Z" level=info msg="mev-boost v0.8.2" module=cli
time="2022-09-16T10:29:57Z" level=info msg="Using genesis fork version: 0x00001020" module=cli
time="2022-09-16T10:29:57Z" level=info msg="using 1 relays" module=cli relays="[{0xafa4c6985aa049fb79dd37010438cfebeb0f2bd42b115b89dd678dab0670c1de38da0c4e9138c9290a398ecd9a0b3110 https://0xafa4c6985aa049fb79dd37010438cfebeb0f2bd42b115b89dd678dab0670c1de38da0c4e9138c9290a398ecd9a0b3110@builder-relay-goerli.flashbots.net}]"
time="2022-09-16T10:29:57Z" level=info msg="Checking relay" module=service relay="https://0xafa4c6985aa049fb79dd37010438cfebeb0f2bd42b115b89dd678dab0670c1de38da0c4e9138c9290a398ecd9a0b3110@builder-relay-goerli.flashbots.net"
time="2022-09-16T10:29:58Z" level=info msg="listening on localhost:18550" module=cli

Its clear that mev-boost client is running on localhost:18550.

This is my Beacon node command on Goreli-Prater test net

docker run -d -it -v /home/lucy/launch/prysm:/root -v /home/lucy/launch/geth/genesis.ssz:/genesis.ssz -v /home/lucy/launch/jwt.hex:/jwt.hex -p 4000:4000 -p 13000:13000 -p 12000:12000/udp --name beacon --net=host gcr.io/prysmaticlabs/prysm/beacon-chain:stable --datadir=/root --genesis-state=/genesis.ssz --accept-terms-of-use=true --rpc-host= --monitoring-host= --execution-endpoint=http://localhost:8551 --jwt-secret=/jwt.hex --suggested-fee-recipient=0x7Db8bD7FF6a856c1715a58BB4fd83BF43519bDa3 --http-mev-relay=http://localhost:18550  --prater

Here is the logs of error after running the above beacon node command

Running on the Prater Testnet
[2022-09-16 10:34:28]  WARN flags: Enabled feature flag enable-only-blinded-beacon-blocks=Enables storing only blinded beacon blocks in the database without full execution layer transactions
[2022-09-16 10:34:28]  INFO node: Checking DB database-path=/root/beaconchaindata
[2022-09-16 10:34:28]  INFO db: Opening Bolt DB at /root/beaconchaindata/beaconchain.db
[2022-09-16 10:34:29]  INFO node: Deposit contract: 0xff50ed3d0ec03ac01d4c79aad74928bff48a7b2b
[2022-09-16 10:34:38]  INFO p2p: Running node with peer id of 16Uiu2HAm2BhfednXjfzBqjYPUWufdBKDVtNdAFoTCWEHMUqVMMzw 
[2022-09-16 10:34:38]  INFO blockchain: --weak-subjectivity-checkpoint not provided. Prysm recommends providing a weak subjectivity checkpoint for nodes synced from genesis, or manual verification of block and state roots for checkpoint sync nodes.
[2022-09-16 10:34:38]  INFO initial-sync: Waiting for state to be initialized
[2022-09-16 10:34:38] ERROR main: could not connect to builder: Get "http://localhost:18550/eth/v1/builder/status": dial tcp connect: connection refused

Here are the logs of my Geth Execution client

docker run -d -it -v /home/lucy/launch/geth:/root -v /home/lucy/launch/geth/genesis.ssz:/genesis.ssz -v /home/lucy/launch/jwt.hex:/jwt.hex -p 8545:8545 -p 30303:30303 --name geth --net=host ethereum/client-go --datadir=/root --http --http.port=8545 --http.addr= --http.vhosts=* --http.api=eth,net,web3,personal --authrpc.port=8551 --authrpc.vhosts=localhost --authrpc.jwtsecret=/jwt.hex -cache 3072 --goerli
WARNING: Published ports are discarded when using host network mode
(base) lucy@lucy-Legion-5-Pro-16ITH6H:~/launch$ docker logs -f geth
INFO [09-16|09:46:52.492] Starting Geth on Görli testnet... 
INFO [09-16|09:46:52.493] Maximum peer count                       ETH=50 LES=0 total=50
INFO [09-16|09:46:52.494] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
INFO [09-16|09:46:52.496] Set global gas cap                       cap=50,000,000
INFO [09-16|09:46:52.498] Allocated trie memory caches             clean=460.00MiB dirty=768.00MiB
INFO [09-16|09:46:52.498] Allocated cache and file handles         database=/root/geth/chaindata cache=1.50GiB handles=524,288
INFO [09-16|09:46:52.625] Opened ancient database                  database=/root/geth/chaindata/ancient/chain readonly=false
INFO [09-16|09:46:52.625] Initialising Ethereum protocol           network=5 dbversion=<nil>
INFO [09-16|09:46:52.625] Writing custom genesis block 
INFO [09-16|09:46:52.631] Persisted trie from memory database      nodes=361 size=51.17KiB time="547.369µs" gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [09-16|09:46:52.631]  
INFO [09-16|09:46:52.631] ------------------------

Am i missing any command on mev-boost client or beacon node? Why my beacon node cannot connect to mev client? Is this docker connection issue?

Please help!!

1 Answer 1


You might need to tweak how networking work across your various docker standalone containers. This line here tells us that your beacon node cannot reach your mev-boost process:

[2022-09-16 10:34:38] ERROR main: could not connect to builder: Get "http://localhost:18550/eth/v1/builder/status": dial tcp connect: connection refused

By default, the bridge network driver will be used when starting a docker standalone container. If you start your mev-boost docker standalone containers like you are doing right now, it will live on its own isolated network island. To fix this issue, you might need to start it using host networking.

That would mean starting mev-boost with something like:

sudo docker run --network host flashbots/mev-boost -goerli  -relay-check -relays=https://0xafa4c6985aa049fb79dd37010438cfebeb0f2bd42b115b89dd678dab0670c1de38da0c4e9138c9290a398ecd9a0b3110@builder-relay-goerli.flashbots.net

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