How to resolve Ipv4 and Ipv6 from ".local" using mDNS in Android

Question

I am trying to resolve IPv4 and IpV6 from ".local" using multicast DNS and I tried https://github.com/posicks/mdnsjava but it unable to resolve required ipv4/ipv6. Alternatively, I found one app which work for me but have no idea how it works.

App Link : https://play.google.com/store/apps/details?id=com.dokoden.dotlocalfinder

Also I am trying to resolve ".local" using Linux Terminal -
Command used to resolve ipv4 avahi-resolve-host-name abc.local -4
Command used to resolve ipv6 avahi-resolve-host-name abc.local -6
and it resolved successfully.

I am tried same command in Android to resolve ".local" but getting Cannot run program "avahi-resolve-host-name": error=13, Permission denied

I am trying this piece of code in Android -

  Process process = Runtime.getRuntime().exec("avahi-resolve-host-name abc.local -4");
  BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
  Log.d("OutPut",in.readLine());

Thanks @rombie18 ,I also tried with root privilege but not get success. — Tanmay Ranjan, Nov 25 '20 at 06:25

score 2 · Accepted Answer · edited Nov 26 '20 at 00:33

Finally, I got success.

I resolved Ipv4 and Ipv6 using mdnsjava dependency i.e.

implementation "xyz.gianlu.mdnsjava:mdnsjava:2.2.1"

For resolving Ipv4 I use this code snippet

for (Record record : new Lookup(localName, Type.A, DClass.IN).lookupRecords()) {
   if (record.getType() == Type.A) {
       ((ARecord) record).getAddress().getHostAddress();
       }
    }

Before writing this code snippet you have to put MuticastLock on connected Wifi using

  WifiManager.MulticastLock multicastLoc = wifiManager.createMulticastLock("mDnsLock");
  multicastLoc.setReferenceCounted(true);
  multicastLoc.acquire();

and after getting ip release multicastLock.

For Ipv6 I used same Ipv4 code snippet only here the record type should be Type.AAAA in place of Type.A

This code works up to Android 10.

People won't easily notice supplementary questions in answers. If you still have a problem then you can either (a) edit your existing question, if the questions are tightly connected; or (b) ask a new question. — halfer, Nov 26 '20 at 00:35

niek tuytel · Answer 2 · 2020-11-24T01:27:52.653

I am not 100% this will work, but as comment is was to large.

check the following permissions in your AndroidManifest.xml

    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

Following links might be usefull:

How to resolve Ipv4 and Ipv6 from ".local" using mDNS in Android

2 Answers2