rich1.0npub1e46n428mcyfwznl7nlsf6d3s7rhlwm9x3cmkuqzt3emmdpadmkaqqjxmcuhttps://nostr.ae/npub1e46n428mcyfwznl7nlsf6d3s7rhlwm9x3cmkuqzt3emmdpadmkaqqjxmcunjumphttps://nostr.ae📅 Original date posted:2011-08-03 🗒️ Summary of this message: Bitcoin's DNS seeds are experiencing issues due to bad nodes, slowing down peer bringup for Android apps. A custom DNS server may be a solution. 📝 Original message:On Wed, 2011-08-03 at 12:04 +0200, Mike Hearn wrote: > This is expected to happen from time to time of course as it's > inherently racy, but there are a lot of bad nodes appearing in the DNS > seeds. > $ nmap -oG /tmp/x -p 8333 `dig +short bitseed.bitcoin.org.uk > dnsseed.bluematt.me bitseed.xf2.org` > ... > Nmap done: 48 IP addresses (25 hosts up) scanned in 9.80 seconds > $ grep -c 'closed' /tmp/x > 6 > So of 48 IPs returned only 19 are actually usable. This is slowing > down peer bringup for the Android apps, which don't currently save the > addresses of last-used peers (yes, I know we should fix this). Its actually much, much less. You forgot to grep for filtered, which are also worthless and you didn't make an actual connection to the node, meaning there is no way to tell if the node has its connection slots full (a node which has the maximum connection count will ack a syn, but will drop the connection after the first message, so nmap thinks the port is open). I just tested and I show 0 accepting from bitseed.xf2.org and 0 from bitcoin.bitcoin.co.uk. dnsseed.bluematt.me rotates every 2 minutes to the most recently checked so it tends to be pretty good if you get it right after a rotate, if you wait to long, those slots fill up quick. > > I was talking to a friend a few days ago about Bitcoin, he seemed > interested. I'm hoping he might take on DNS seeding as a project. A > custom DNS server that watches the network to find long-lived peers > that run the latest version would be helpful for resolving this kind > of thing. Point him to https://github.com/TheBlueMatt/dnsseed it could use a bit of cleanup, but it works. If a different DNS Server were used to could pull directly from the database in a more dynamic way it would probably work better too (it was originally set up on MySQL and PowerDNS, but that is quite a resource hog compared to SQLite and BIND, but the original backend is still there and could work if you have a beefy enough server). Matt -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 836 bytes Desc: This is a digitally signed message part URL: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20110803/3cbcb018/attachment.sig>