Package godnsbl lets you perform RBL (Real-time Blackhole List - https://en.wikipedia.org/wiki/DNSBL) lookups using Golang
The command-line tool in cmd demonstrates the use of goroutines to perform concurrent lookups.
To test:
go get github.com/mrichman/godnsbl
cd $GOPATH/src/github.com/mrichman/godnsbl/cmd/godnsbl
go run main.go 127.0.0.2
The output will be a JSON-formatted list of results with the following fields:
[
...
{
"address":"127.0.0.2",
"listed":true,
"text":"Client host blocked using Barracuda Reputation, see http://www.barracudanetworks.com/reputation/?r=1\u0026ip=127.0.0.2",
"error":false,
"error_type":null
}
...
]