Topic: A Basic Guide/Tutorial for Creating DNS Seeders (Read 7124 times)

I would like to say a BIG THANK YOU to the original creator of this thread @PereguineBerty, as this has served as the main setup guide for the bitcoin-seeder for exactly 6 years to the day!

A lot has changed since then, and earlier this year I took it upon myself to improve the functionality of the seeder app and also took the time to write a complete step-by-step guide for its use.

All details, including a copy of the full guide can be found here: https://bitcointalksearch.org/topic/dns-seeder-setup-guide-using-the-generic-seeder-5239304

You are missing some steps in your DNS setup.

First of all, you are required to create both an NS and "A" record, and it looks like you have only created an NS record (and even that I don't think is true because you seem to be trying to use your domains default ns1 nameserver). Next, your NS record must point to the "A" record, and your "A" record must point to the ip address of your vps. And lastly, your arguments for running the seeder app are mixed up a bit.

To correct your current setup I would do something like this:

1) Create an "A" record that points to the ip address for your vps (ex: 111.222.123.231). You can give it any name you want but for this example lets call it vps.seederio.com
2) Create a new NS record and point it to the "A" record you just created. The NS record can also be called whatever you want but for this example lets call it seeder.seederio.com
3) On your vps, setup the DNS seeder app according to the instructions (I believe you already did this step)
4) Run the following cmd on the vps to start crawling your coins network and simultaneously start listening for DNS requests:


5) Wait a few minutes to allow the seeder to find the "good" nodes on your network.
6) You can test that your seeder is working by using the following cmd, but keep in mind that these values can be cached and may not always give a good result even if it is working:


If all is working it should return a list of "good" ip addresses that are valid seed nodes for your network. An alternative to using the nslookup cmd is to use an online service to check if your seeder is working. You can visit this page after your seeder is running to see if it is working (you should see lots of ip addresses and green checkmarks. Seeing no ip addresses and red X's means something isnt working): https://www.whatsmydns.net/#A/seeder.seederio.com

7) That's it! You are done! 

Still no result. When i put I've got:
Seeder is working on port 53. UFW is disable

I got it working on my end by using a subdomain so something like this:

Hi,
I'm trying to setup bitcoin seeder, but i'm having problem with correct DNS setup.

Domain is registered in Goddady, and i have DNS record:


VPS in Vultr, with IPv6 and reverse DNS



Command to run seeder (with root priv):


But after command:
I've got following message:


For I've got the same result. Could you help me with this problem?

I believe clientVersion is the protocol version - I believe the seeder is only saving the "protocolversion" from the nodes it connects to and does not do anything with the "version" (i.e. from -getinfo)

If you check you'll see that clientVersion doesn't get overwritten with a different value for each if statement so it will always contain the protocol version.

The variable "clientVersion" is compared with REQUIRE_VERSION(which is a protocol version) in the function IsGood,
while it is compared with 31900(which seems to be a client version v0.3.19) in the function GetBanTime.
What on earth should "clientVersion" be compared with? Client version or protocol version?

Hey guys,

I've been trying to get a bitcoin-seeder working myself, but i keep getting stuck trying to set up a nameserver..

The things i have:
1. VPS where i want to run the dnsseed on (12.345.678.90)
2. Sub-domain (seed.example.com)
3. Sub-domain2 (ns0.example.com)

The steps i took are:
1. Go to the subdomain seed.example.com and go to DNS settings.
2. Select NS-record and put "ns0.example.com" in it
3. Go to sub-domain "ns0.example.com" and put a A-record with the VPS ip "12.345.678.90"

When i run "dig -t NS seed.example.com"  i get an servfail and it wont show anything:

When i run "dig -t A ns0.example.com" i do get the A record forwarding to the VPS IP:

When i try to run the dnsseed program it wont find my any seeds either this way:
./dnsseed -h seed.example.com -n ns0.example.com -p 5353
https://i.gyazo.com/f2b52ec55e1b8d6ce3737e08feb47a5f.png

When i go back to the sub-domain seed.example.com and remove the NS record and change it with a A record directly to the VPS i get:

And when i run dnsseed with the following parameters it does find seeds, but it wont broadcast them to the dns:
./dnsseed -h seed.example.com -n 12.345.678.90 -p 5353
https://i.gyazo.com/04db23b1de72e8080aa45ceb15e1d2fc.png


It seems like whatever i try, i keep getting servfail when i set a NS to anything. Does anyone have any clue what i'm doing wrong and what i should change to get it working?

Thats' looks very helpful, but still not able to have anything working
Just pm'ed you!

You can also make a systemd service.

nano /etc/systemd/system/seed.service

put this in, customize where needed:

[Unit]
Description=COIN dns seeder
After=network.target

[Service]
WorkingDirectory=//coin-seeder
ExecStart=//coin-seeder/dnsseed -h -n -m [email protected]
Restart=on-failure
RestartSec=10
User=root
StandardOutput=syslog
StandardError=syslog
SyslogIdentifier=COIN-seeder

[Install]
WantedBy=multi-user.target

save & exit
systemctl daemon-reload
systemctl enable seed
systemctl start seed

crontab is your friend  

sudo crontab -e # You're starting the seeder as root

Then add the line : @reboot // [-]

That should do it.

The OP, PereguineBerty's Guide is very useful, but could use some copy-editing.

Start with the latest source code, (from the original author, SIPA (Peter Wuille), as written for bitcoin)
   and   change things specific to your coin.

You can compare what we've done for Bitmark:
https://github.com/sipa/bitcoin-seeder/compare/master...project-bitmark:master

Basically, you should customize which node versions your seeder will report as good, the required blockheight, the protocol version, the fixed seed nodes your seeder needs to get started, the "magic" bytes of pchMessageStart[] and of course, the P2P port for your coin.

PM me if you need more help.

What version of Ubuntu are you running ?  

On Ubuntu 14.04 LTS & 16.04 LTS, run DNS seeder via /etc/rc.local
I ilke to start a detached screen session, (called seeder-screen) everytime on boot.

(Note: on Ubuntu 18.04 LTS, systemd has eliminated /etc/rc.local setups. In this OS, you can set up a systemd unit file in /etc/systemd/system, but it's not possible to pass parameters via the 'ExecStart' spec, so the binary should be hardcoded with your particular parameters, such as name of sub-domain served and the hosting IP address, etc.)


example:

You can check functioning of the seeder by attaching to the seeder-screen session.

I'm a little confused as to how one customizes the seeder software itself so that it crawls a specified altcoin on a specified port.  Is there anywhere the shows what you have to customize so that the seeder is crawling the proper network?

Can anyone tell me how to run dns seeder as service on ubuntu? I want to be sure that my dns seeder is automatically running after server reboot

Recently I face a similar problem and find this other useful doc in dogecoin seeder code:

Thanks, esotericizm - yours is an interesting approach to seeder setup and may be an alternative for people who have difficulties with the Sipa seeder.

When the seeder is initialy run, it displays a real-time update of the stats of connected peers although the info it provides isn't always 100% reliable (at least not in my experience).

I find the best way is to check if it's working is by running your wallet, making sure that no nodes are available in yourcoin.config file. If the wallet doesn't pick up any new connections after a few seconds (but give it a minute or two to test), something isn't configured correctly.


Excellent answer, Yarkol. This will be added to the instructions.

Most of the important changes needed are included in the git commit history mentioned above and also in the seeder instructions but this one hasn't been mentioned. It could cause a real pain for devs if the seeder starts kicking nodes at specific blocks, so they should be made aware of this.

If you have a server running a form of *nix you can install and setup bind9. That way all you have to do is add some nodes to your zone file. No need to use bitcoin seeder.

Of course this will require manually updating your zone file to add new nodes.

Good guide otherwise.


Easy way to test is to use a site like https://www.whatsmydns.net and search the A record. If its working it should display a list of your peers/nodes or you can use 'dig' if on a *nix machine.

Nodes that have blocks less than that number are
discarded by the crawler as not good candidates,
see IsGood db.h:108