DNS load balancing

mixou

Hello,

I don't know if I'm on the right forum section, I didn't find the section for the load-balancing.

I have a pool of public DNS and private DNS on a docker swarm. Public dns are listening on two ip adresses on udp/tcp 530 port, private are listening on te port 531.

To load balance and change the Dns port to 53 I plan to use the load-balancer functionality.

But once implemented it doesn't work and I don't know how to troubleshoot the problem

Some screenshots

And the relyd.conf


log updates 
timeout 1000 
table <mysqld>{
	10.31.1.10 retry 5
	10.31.1.40 retry 5
}
table <public-dns>{
	10.33.1.10
	10.33.1.20
}
dns protocol "dnsproto" {
	tcp { nodelay, sack, socket buffer 1024, backlog 1000 }
}
redirect "mysqlserver" {
  listen on 10.31.1.100 port 3306
  forward to <mysqld>port 3306 check tcp 
}
relay "pubdns" {
  listen on 10.33.1.100 port 53
  protocol "dnsproto"
  forward to <public-dns>port 530 mode loadbalance check icmp 
}</public-dns></mysqld></public-dns></mysqld>

Thank you for the help

jimp

The DNS load balancing feature doesn't see much testing, it's possible there is an issue there, or it may just be a limit of relayd. Last time I tried it, it worked, but I also wasn't trying to have it hit a different internal port.

How are you testing it to see if it works? Have you tried other monitoring types than ICMP?

One major thing to be aware of, when relayd does dns balancing it acts like a proxy, so your DNS servers will only see the address of the firewall itself and not the clients. Depending on your DNS server config that may make a difference in how it handles the queries.