Litecoin-seeder is a crawler for the Litecoin network, which exposes a list of reliable nodes via a built-in DNS server.
Features:
- regularly revisits known nodes to check their availability
- bans nodes after enough failures, or bad behaviour
- accepts nodes down to v0.5.0 to request new IP addresses from, but only reports good post-v0.6.9 nodes.
- keeps statistics over (exponential) windows of 2 hours, 8 hours, 1 day and 1 week, to base decisions on.
- very low memory (a few tens of megabytes) and cpu requirements.
- crawlers run in parallel (by default 96 threads simultaneously).
Assuming you want to run a dns seed on dnsseed.example.com, you will need an authorative NS record in example.com's domain record, pointing to for example vps.example.com:
$ dig -t NS dnsseed.example.com
;; ANSWER SECTION dnsseed.example.com. 86400 IN NS vps.example.com.
On the system vps.example.com, you can now run dnsseed:
./dnsseed -h dnsseed.example.com -n vps.example.com
If you want the DNS server to report SOA records, please provide an e-mailadres (with the @ part replaced by .) using -m.
Typically, you'll need root privileges to listen to port 53 (name service).
One solution is using an iptables rule (Linux only) to redirect it to a non-privileged port:
$ iptables -t nat -A PREROUTING -p udp --dport 53 -j REDIRECT --to-port 5353
If properly configured, this will allow you to run dnsseed in userspace, using the -p 5353 option.