absolute-seeder
==============

Absolute-seeder is a crawler for the Absolute 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 v0.12.2.3 to request new IP addresses from,
  but only reports good post-v0.12.2.4 nodes (currently v0.12.2.5 only).
* 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).

REQUIREMENTS
------------

$ sudo apt-get install build-essential libboost-all-dev libssl-dev

USAGE
-----

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-mail address (with the @ part replaced by .) using -m.

OPTIONS
-------

"-h <host>       Hostname of the DNS seed\n"
"-n <ns>         Hostname of the nameserver\n"
"-m <mbox>       E-Mail address reported in SOA records\n"
"-s <seconds>    Number of seconds to sleep before printing stats (default 1)\n"
"-t <threads>    Number of crawlers to run in parallel (default 96)\n"
"-d <threads>    Number of DNS server threads (default 4)\n"
"-p <port>       UDP port to listen on (default 53)\n"
"-o <ip:port>    Tor proxy IP/Port\n"
"-i <ip:port>    IPV4 SOCKS5 proxy IP/Port\n"
"-k <ip:port>    IPV6 SOCKS5 proxy IP/Port\n"
"-w f1,f2,...    Allow these flag combinations as filters\n"
"--simplelog     Do not use advanced stats output, use simple log-like one instead\n"
"--testnet       Use testnet\n"
"--wipeban       Wipe list of banned nodes\n"
"--wipeignore    Wipe list of ignored nodes\n"

COMPILING
---------
Compiling will require boost and ssl.  On debian systems, these are provided
by `libboost-dev` and `libssl-dev` respectively.

$ make

This will produce the `dnsseed` binary.


RUNNING AS NON-ROOT
-------------------

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.