How to determine if ISP is blocking Ethereum traffic

Question

My "Ethereum Wallet" from ethereum.org used to connect to several peers. A while ago I noticed it was taking longer and longer to sync and the number of peers dropped. It got worse, and seldom connected to more than 1 peer. Now, it connects to none.

1. Is it possible that ISPs are blocking Ethereum traffic?
2. How can I determine if my ISP is blocking Ethereum traffic?
3. If ISPs do block the Ethereum network, how do we use Ethereum?

Answer 1

1. It is possible an ISP is blocking traffic but unlikely. In the UK they typically only block traffic under court order.

2. the following options could help you identify where the bottleneck is,

You can run the tracert command and use one of the ip addresses of a peer.

On windows it looks like this,

C:\>tracert 192.168.1.254

Tracing route to 192.168.1.254 over a maximum of 30 hops
---------------------------------------------------
1      2 ms       3 ms       2 ms      10.0.0.2
2     75 ms      83 ms      88 ms      10.0.0.1
3     73 ms      79 ms      93 ms      192.168.1.254

Trace complete.

This will at least show you the route between you and the peer that you could connect to is reachable, similar with

C:\Users\Admin\Desktop>tcping.exe 192.168.1.254 30303
C:\Users\Admin\Desktop>tcping.exe 192.168.1.254 30301 

with the tracert output you should be able to see any hops along the way that may be congested or dropping network packets.

if you can reach the peer and getting a response back then most likely the ISP is not blocking traffic. If network packets are getting dropped along the route and your getting no response then it may indicate that something is blocking traffic.

It might be that only a specific type of traffic is being blocked such TCP/UDP on a specific port.

3. You can try using a VPN connection and connecting to a different country that does not block ethereum traffic.

Answer 2

To add to the other answer, and comments, you could take a look at the Tor Project's OONI probe tool, which is:

Open Observatory of Network Interference A free software, global observation network for detecting censorship, surveillance and traffic manipulation on the internet

It basically works by checking what is accessible from your machine, and comparing it to what is known to be accessible from elsewhere. (I think it can be configured for specific IP addresses, but you'll have to have a play around with it - I haven't used it in a while.)

(Raw GitHub link, here.)

Answer 3

If you are using --light sync that could be a problem.

Decempber 5 Pető Zoltán @micahaza states that the --light mode is buggy and not to use it on the Mist Gitter channel. It seems that the problems with light sync are causing low network usage. It may be worth a post there to see if they have fixed it.

beyond that, syncing is just slow period... check your progress with geth attach in the javascript console.

Answer 4

1. Yes.
2. Similar to @RichardHorrocks' answer, what you can do is to set up Ethereum nodes on machines in the cloud. You can do things like measure your bandwidth etc. and see what you can expect from these nodes. You can also compare inter-cloud-node performance. Then bootstrap your computer to these nodes. If the measured performance is far below what you expect, you know you're being blocked... or if you can't connect to one of the machines entirely. It's pretty hard to know that you're NOT being blocked. You can never prove you're not being blocked.
3. As others have pointed out, you can use a VPN or some other kind of tunnel. Surprisingly, no one has mentioned connecting to a node without a full Ethereum client (e.g., by using a relay like MyEtherWallet -- make sure you understand what you're using and that you're using it properly to mitigate risks). You can also use a wallet-hosting service where a third-party keeps you keys for you (eep!).