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?
  • Very interesting question given recent net neutrality fiasco. – Thomas Jay Rush Dec 2 '17 at 16:20
  • one way might be to compare your traffic statistics with a known good connection. google et.al has developed measurementlab.net, which may help? I think once a baseline of what is good is established, then you can compare a suspected connection with good and see the difference. measurementlab.net has a tool NDT (Network Diagnostic Tool), which could be very useful to test scenarios like this. measurementlab.net/tests/ndt – drequinox Dec 19 '17 at 9:51
  • Are you trying to connect at work? – Samuel Dare Dec 19 '17 at 14:44
  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,


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

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

  1. You can try using a VPN connection and connecting to a different country that does not block ethereum traffic.
  • If all from the above seem ok, you might want to look at firewall rules on your computer or home/business router. If using a VM in the cloud check the security groups. – Lismore Dec 19 '17 at 14:34
  • you can also open a terminal/command prompt then attach to geth and manually add a known peer with admin.addPeer() – Lismore Dec 19 '17 at 14:38
  • I have a full node, "Ethereum Wallet", installed. I'm comfortable working from the terminal; however, not familiar with geth. Is it bundled with and accessible from Ethereum Wallet? Is there a way to get peers and their IP addresses using dev tools within Ethereum Wallet or must I use geth? – user11495 Dec 20 '17 at 3:27
  • Oh, and thanks for the answers! About part 3. I'm sure most people are excited about cryptocurrencies and the new tools and services that will emerge as a result of Ethereum's programmable blockchain. If entire countries are blocking or even throttling the ethereum network, it will all end before it ever has a chance. VPN'ing to another country to use a full node decentralized wallet seems to cumbersome for wide adoption. Is this truly the only solution or have the leading developers taken into account that governments/corporations may simply shut it all down by censorship? – user11495 Dec 20 '17 at 3:40
  • #2 Does not actually show anything. Firstly, if you are connected to your peer, that only tells you that that particular connection may not have been censored. Secondly, a successful ping does not mean that your connection is not being blocked. Your ISP may be doing deep packet inspection or some other rule-based filter; this could allow ICMP (ping) packets to traverse the network but blocks others. – lungj Dec 22 '17 at 6:13

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.)


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.

  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!).

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