maxcoin-seeder is a crawler for the MaxCoin network, which exposes a list of reliable nodes via a built-in DNS server. It is a fork of bitcoin-seeder.
FEATURES
- Regularly revisits known nodes to check their availability
- Bans nodes after enough failures, or bad behaviour
- Accepts nodes down to v0.3.19 to request new IP addresses from, but only reports good post-v0.3.24 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).
REQUIREMENTS
- Debian based GNU/linux without systemd-resolvd (recommended Ubuntu 16.04).
- Have a public IP Address with access to the port 53
- Have a domain name and access to configure registries on it.
- build-essential
- libboost-all-dev
- libssl-dev
Note: if your OS has systemd-resolvd reference to Known the
KNOWN ISSUESsection
Install dependencies:
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$ sudo apt-get install build-essential libboost-all-dev libssl-dev
COMPILING
First we get the repository maxcoin-seeder code
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$ git clone https://github.com/Max-Coin/maxcoin-seeder
$ cd maxcoin-seeder
Compiling will require boost and ssl. On debian systems, these are provided by libboost-dev and libssl-dev respectively.
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$ make
This will produce the dnsseed binary.
USAGE
Best practice is to have a maxcoin daemon with the blockchain on the same server as a public node
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:
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$ 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:
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./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.
Usage with testnet enabled
Best practice is to have a maxcoin daemon with the testnet blockchain on the same server as a public node
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./dnsseed --testnet -h dnsseed.example.com -n vps.example.com
Usage with tor enabled
Server Side
Requirement: install tor (# apt install tor) if you follow this tutorial How To Setup tor node Remember that Maxcoin uses 8668 tcp port and 18668 for the testnet
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./dnsseed -o 127.0.0.1:9050 -h dnsseed.example.com -n vps.example.com
Client Side
Requirement: install tor (# apt install tor)
First, you can just add it to the command line:
$ maxcoind -proxy=127.0.0.1:9050 -addnode=mqrlomy4wdddohem.onion:8668 -listen -debug=tor
Or you can add it to your maxcoin.conf file:
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proxy=127.0.0.1:9050
addnode=mqrlomy4wdddohem.onion:8668
listen=1
debug=tor
The debug param tells it to print info about tor when the service comes up so you can see if anything is not working.
When you bring up the service, you should see a statement like
NOTE: mqrlomy4wdddohem.onion:8668 is an official maxcoin tor dnsseed address.
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:
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$ 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.
KNOWN ISSUES
SPECIAL INSTRUCTIONS FOR UBUNTU USERS
All Ubuntu releases starting with 16.10 (first released in October 2016) come installed with systemd-resolved, which effectively prevents the seeder’s built-in DNS server from working correctly. This is due to both applications requiring use of port 53, and systemd-resolved takes priority by default. There are a few ways to resolve this issue:
1.- Force the seeder to bind to a specific IP address by adding the following argument to the terminal cmd: -a <ip address>. This is the recommended solution as it doesn’t require disabling of any operating system services.
Example:
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sudo ./dnsseed -h dnsseed.example.com -n vps.example.com -a 123.231.123.231
2.- Disable binding of systemd-resolved to port 53 by editing the /etc/systemd/resolved.conf file and adding this line to the bottom of the file:
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DNSStubListener=no
Save and reboot, and now systemd-resolved will no longer interfere with the seeder’s DNS server.
NOTE: This method is only supported by systemd 232 and newer. You can check your version of systemd with the cmd:
systemctl --version
3.- Completely disable the systemd-resolved service with the following cmds (not recommended as it may cause undesired side-effects if you use the same server for anything other than running the seeder app):
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sudo systemctl disable systemd-resolved
sudo systemctl stop systemd-resolved
FIX KNOWN ISSUES AFTER PROCEDURE 2 OR 3
Sometimes after the procedure 2 or 3 there is an issue with the dns resolving addresses so it is recommended to follow this solution:
1.- Delete the resolv.conf file:
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sudo rm -f /etc/resolv.conf
2.- Edit, add dns servers configs and write the file.
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sudo vim /etc/resolv.conf
Example config at the /etc/resolv.conf file:
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nameserver 1.1.1.1
nameserver 1.0.0.1
~
3.- Set linux file system file attribute to cannot be modified
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sudo chattr +i /etc/resolv.conf
4.- Restart the network config depeding on your configuration
Option 1:
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sudo /etc/init.d/networking restart
Option 2:
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sudo netplan apply
ToDo
- Support Linux systems with systemd-resolvd service
- Support the new tor v3 addresses
- Add to the virtual machines images with an autoconfig script.
CONTACT
Developers