how to fix this error:"java.net.UnknownHostException: DNS service refused [response code 5]"

[smithice]

I use skydns as my dns server.when use ping or nslookup ,all is ok.when use java:
`import java.net.InetAddress;
import java.net.UnknownHostException;

public class FindDomain {

static {
	System.setProperty("sun.net.spi.nameservice.nameservers", "192.168.48.222");
	System.setProperty("sun.net.spi.nameservice.provider.1", "dns,sun");	
}

public static void main(String[] args) {

	try {
		getHostByIPAddress();

	} catch (UnknownHostException e) {
		e.printStackTrace();
	}

}

public static void getHostByIPAddress() throws UnknownHostException {
	System.out.println(InetAddress.getByName("test.mydnsserver.com").getHostAddress());
}

}get below error:java.net.UnknownHostException: DNS service refused [response code 5]
at sun.net.spi.nameservice.dns.DNSNameService.resolve(DNSNameService.java:180)
at sun.net.spi.nameservice.dns.DNSNameService.lookupAllHostAddr(DNSNameService.java:291)
at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323)
at java.net.InetAddress.getAllByName0(InetAddress.java:1276)
at java.net.InetAddress.getAllByName(InetAddress.java:1192)
at java.net.InetAddress.getAllByName(InetAddress.java:1126)
at java.net.InetAddress.getByName(InetAddress.java:1076)
at com.hundsun.FindDomain.getHostByIPAddress(FindDomain.java:33)
at com.hundsun.FindDomain.main(FindDomain.java:23)
`
am i missing some setting in skydns?

[miekg]

Interesting, do you have any tcpdumps when this happens?

[miekg]

Also, are you able to replicate this with coredns? (github.com/coredns/coredns)

[smithice]

here is the tcpdumps:
Standard query 0x9443 ANY test.mydnsserver.com Standard query response 0x9443 Refused ANY test.mydnsserver.com
it seems like the issue (#97)
JAVA InetAddress seem use 'ANY' query...

[miekg]

ANY!!!???1!? Why?

We block ANY in SkyDNS because it is such a useless query. (Didn't port that particular feature over to CoreDNS, because filtering is done in a separate middleware).

Think in CoreDNS you'll by served A records when doing an ANY lookup, meaning the above code may work.

Can this ANY behavior be disabled in Java?

[smithice]

i can't find InetAddress's source code...
CoreDNS allow ANY lookup ,but find following error:
Exception in thread "main" java.net.UnknownHostException: DNS record not found at sun.net.spi.nameservice.dns.DNSNameService.resolve(DNSNameService.java:186) at sun.net.spi.nameservice.dns.DNSNameService.lookupAllHostAddr(DNSNameService.java:291) at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323) at java.net.InetAddress.getAllByName0(InetAddress.java:1276) at java.net.InetAddress.getAllByName(InetAddress.java:1192) at java.net.InetAddress.getAllByName(InetAddress.java:1126) at java.net.InetAddress.getByName(InetAddress.java:1076) at FindDomain.getHostByIPAddress(FindDomain.java:49) at FindDomain.main(FindDomain.java:43)
here is tcpdump:
Standard query 0x8c4e ANY test.mydomain.com Standard query response 0x8c4e ANY test.mydomain.com SOA ns.dns.mydomain.com
(nslookup or ping is ok )

here is my Corefile:
.:53 { etcd mydomain.com { stubzones path /skydns endpoint http://127.0.0.1:2379 upstream 8.8.8.8:53 } prometheus cache 160 mydomain.com loadbalance proxy . 8.8.8.8:53 }

[miekg]

[ Quoting <[email protected]> in "Re: [skynetservices/skydns] how to ..." ]

i can't find InetAddress's source code... CoreDNS allow ANY lookup ,but find following error: ` Exception in thread "main" java.net.UnknownHostException: DNS record not found at sun.net.spi.nameservice.dns.DNSNameService.resolve(DNSNameService.java:186) at sun.net.spi.nameservice.dns.DNSNameService.lookupAllHostAddr(DNSNameService.java:291) at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323) at java.net.InetAddress.getAllByName0(InetAddress.java:1276) at java.net.InetAddress.getAllByName(InetAddress.java:1192) at java.net.InetAddress.getAllByName(InetAddress.java:1126) at java.net.InetAddress.getByName(InetAddress.java:1076) at FindDomain.getHostByIPAddress(FindDomain.java:49) at FindDomain.main(FindDomain.java:43) ` here is tcpdump: ` Standard query 0x8c4e ANY test.mydomain.com Standard query response 0x8c4e ANY test.mydomain.com SOA ns.dns.mydomain.com `

Yes, supported, but returns NODATA (I think), can't really see. What does `dig ANY @coredns_server_ip test.mydomain.com` return?

(nslookup or ping is ok ) here is my Corefile: ` .:53 { etcd mydomain.com { stubzones path /skydns endpoint http://127.0.0.1:2379 upstream 8.8.8.8:53 } prometheus cache 160 mydomain.com loadbalance proxy . 8.8.8.8:53 } `

Yes, supported but not doing the right thing. We could make ANY returns all A and AAAA records to accomodate this usecase, but I'm not a fan. Is there anything easy on the java side that could be done here?

[smithice]

why return 'NODATA'? i already add A record to etcd.
am i missing something?
here is dig ANY,and A query
dig ANY @192.168.48.223 test.mydomain.com
`
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.62.rc1.el6 <<>> ANY @192.168.48.223 test.mydomain.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 36889
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;test.mydomain.com. IN ANY

;; AUTHORITY SECTION:
mydomain.com. 5 IN SOA ns.dns.mydomain.com. hostmaster.mydomain.com. 1492736874 7200 1800 86400 60

;; Query time: 5 msec
;; SERVER: 192.168.48.223#53(192.168.48.223)
;; WHEN: Fri Apr 21 09:10:16 2017
;; MSG SIZE rcvd: 88
`

`
dig A @192.168.48.223 test.mydomain.com

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.62.rc1.el6 <<>> A @192.168.48.223 test.mydomain.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27650
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;test.mydomain.com. IN A

;; ANSWER SECTION:
test.mydomain.com. 5 IN A 192.168.48.106

;; Query time: 2 msec
;; SERVER: 192.168.48.223#53(192.168.48.223)
;; WHEN: Fri Apr 21 09:12:12 2017
;; MSG SIZE rcvd: 50
`

[smithice]

Cordns supported ANY lookup indeed! InetAddress is common use case in Java. am i missing something in etcd or Coredns config?

[miekg]

[ Quoting <[email protected]> in "Re: [skynetservices/skydns] how to ..." ]

Cordns supported ANY lookup indeed! InetAddress is common use case in Java. am i missing in etcd or Coredns config?

No you're not missing something. Java is doing it wrong. Doing an ANY lookup to find A/AAAA records is not the correct way of doing the lookup. But we can extend the lookup mechanism to return A/AAAA in this case. /Miek

…

-- Miek Gieben

[smithice]

thanks a lot!!

[miekg]

[ Quoting <[email protected]> in "Re: [skynetservices/skydns] how to ..." ]

Closed #315.

Why did you close it? You're want us to reply to ANY in CoreDNS? /Miek

…

-- Miek Gieben

[smithice]

yes,i thought it can be fix in CoreDNS,but it is a problem in skydns.