{"type":"rich","version":"1.0","author_name":"npub1e46n428mcyfwznl7nlsf6d3s7rhlwm9x3cmkuqzt3emmdpadmkaqqjxmcu","author_url":"https://nostr.ae/npub1e46n428mcyfwznl7nlsf6d3s7rhlwm9x3cmkuqzt3emmdpadmkaqqjxmcu","provider_name":"njump","provider_url":"https://nostr.ae","html":"📅 Original date posted:2011-08-03\n🗒️ 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.\n📝 Original message:On Wed, 2011-08-03 at 12:04 +0200, Mike Hearn wrote:\n\u003e This is expected to happen from time to time of course as it's\n\u003e inherently racy, but there are a lot of bad nodes appearing in the DNS\n\u003e seeds.\n\n\u003e $ nmap -oG /tmp/x -p 8333 `dig +short bitseed.bitcoin.org.uk\n\u003e dnsseed.bluematt.me bitseed.xf2.org`\n\u003e ...\n\u003e Nmap done: 48 IP addresses (25 hosts up) scanned in 9.80 seconds\n\n\u003e $ grep -c 'closed' /tmp/x\n\u003e 6\n\n\u003e So of 48 IPs returned only 19 are actually usable. This is slowing\n\u003e down peer bringup for the Android apps, which don't currently save the\n\u003e addresses of last-used peers (yes, I know we should fix this).\nIts actually much, much less.  You forgot to grep for filtered, which\nare also worthless and you didn't make an actual connection to the node,\nmeaning there is no way to tell if the node has its connection slots\nfull (a node which has the maximum connection count will ack a syn, but\nwill drop the connection after the first message, so nmap thinks the\nport is open).\nI just tested and I show 0 accepting from bitseed.xf2.org and 0 from\nbitcoin.bitcoin.co.uk.  dnsseed.bluematt.me rotates every 2 minutes to\nthe most recently checked so it tends to be pretty good if you get it\nright after a rotate, if you wait to long, those slots fill up quick.\n\u003e \n\u003e I was talking to a friend a few days ago about Bitcoin, he seemed\n\u003e interested. I'm hoping he might take on DNS seeding as a project. A\n\u003e custom DNS server that watches the network to find long-lived peers\n\u003e that run the latest version would be helpful for resolving this kind\n\u003e of thing.\nPoint him to https://github.com/TheBlueMatt/dnsseed it could use a bit\nof cleanup, but it works.\nIf a different DNS Server were used to could pull directly from the\ndatabase in a more dynamic way it would probably work better too (it was\noriginally set up on MySQL and PowerDNS, but that is quite a resource\nhog compared to SQLite and BIND, but the original backend is still there\nand could work if you have a beefy enough server).\n\nMatt\n-------------- next part --------------\nA non-text attachment was scrubbed...\nName: signature.asc\nType: application/pgp-signature\nSize: 836 bytes\nDesc: This is a digitally signed message part\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20110803/3cbcb018/attachment.sig\u003e"}