How can my Ethereum node accept remote connections?

Question

I need to use Web3 on some Python and Javascript applications i'm creating, so i decided to setup a light node on a VPS. The node seems to work, but i'm having troubles accessing it from outside the vps. I'm making sure to serve the RPC API and i tried everything, but i still can use web3 from inside the vps.

w3 = Web3(Web3.HTTPProvider('http://<MY-IP>:8545'))
print(w3.isConnected())

Gives False.

Instead, if i try to do the same from my local VPS where the node is hosted i get True.

Here is how i'm starting the node:

geth --syncmode "light" --rpc --rpcport 8545 --rpcaddr 0.0.0.0 --rpccorsdomain "*" --rpcapi "eth,web3"

I know that it's not a good practice to make the node available to any remote connection, but i'm not storing private keys or balances, i just want to use it to get blokchain data from web3 and i'll see if there is a way to make it accept only specific IPs. How can i make it accept remote connections?

Can the problem be that port 8545 is refusing remote connections? Or is it something else?

Answer 1

First, you should make sure you are using a fairly new geth version. I tested on my recently downloaded version from the official download site

My local version is

$ ./geth version
Geth
Version: 1.9.25-stable
Git Commit: e7872729012a4871397307b12cc3f4772ffcbec6
Git Commit Date: 20201211
Architecture: amd64
Protocol Versions: [65 64 63]
Go Version: go1.15.6
Operating System: linux
GOPATH=
GOROOT=go

Second, you should make sure you use the new flags, the ones you listed are deprecated and will be removed in the future.

--rpc --rpcport 8545 --rpcaddr 0.0.0.0 --rpccorsdomain "*" --rpcapi "eth,web3"

Should be replaced with

--http --http.port 8545 --http.addr 0.0.0.0 --http.corsdomain '*' --http.api 'eth,web3'

Lastly, you also need to enable http.vhosts and allow any or only your domain.

You can do this with

--http.vhosts '*'

When you start the node, you should see this line

INFO [02-17|14:32:16.975] HTTP server started                      endpoint=[::]:8545 cors=* vhosts=*

Even after this line was displayed in the console, you still might not be able to connect to it right away.

After the node boots up, which can take a while, you will be able to connect to it.