I have the same issue. I did a full factory data reset to determine it was FF.

Thanks for the report! I informed the Firefox devs and they luckily detected this problem already and fixed it. But the fix will be coming in Fx 43. Which comes out December 14.

The fix is in: Bug 1194049 - NsdManager increases power consumption

You can also test out the Beta version which already has this fix: https://www.mozilla.org/en-US/firefox/channel/#beta

Report back and let us know if Beta gets rid of the battery drain issue.

Good enough. But there might be a problem or two here: 1 Used the Firefox Beta off the Android Store to see if it solved the problem. It was marked as version 43. It most definitely does not fix the problem: Went to a full charge, reset the phone, opened up the Beta Firefox for a bit, closed it, checked a few hours later, and the mdnsd process was up to 5 or 6%. 2 In the referenced bug report, about 4/5 of the way down, a developer states that the problem may not be fixed. So I'm not sure that this is a slam dunk fix yet.

So: I had to uninstall Firefox. I miss my more secure browser, no way to block things reliably in Chrome. But I can't live with a four or five hour battery life, I can't keep that close to an outlet at work. And, just to reiterate: The Beta on the Google Store has definitely not fixed the bug. If that Beta is the future V. 43 of Firefox for Android, the bug fix hasn't done its job. One more thing. Over the past twelve months or so this mdnsd process has intermittently popped up on random forums as a problem on multiple apps: By the reports, besides some early discussion in Bugzilla, some kind of drone flight control app and an Ebay app. It's not clear from the reading whether this is some general problem with the multicast discovery (I think that's what this is) or whether it's a problem with the way the developers are using the library. However: Right about the same time Firefox 42 for android was released, on various phone forums all over, there are people who have suddenly been bitterly complaining about lost battery life, and that includes the Verizon support pages. Most of them have no idea that it's Firefox's inclusion of whatever the heck mdsnd is, but this is beginning to grow into a >big< problem. Firefox wants to be big on the Android platform. Android is mainly phones. Phones have limited battery life. Security issues and crashes may be hit or miss, but users sweat battery life each and every day. Once word gets out that Firefox is a vector on this somehow, there may be a mass abandonment of the browser. This has to be addressed, properly, ASAP. (Of course, every bug complaint says that.. But I suspect this might have some wings.)

You definitely have a point here and I tried to raise the severity of this with the devs for the exact reasons you mentioned despite my calm reply. ;)

One of them is investigating to see if they can rip out the mdnsd feature.

Battery drain is a huge issue in my eyes and I initially assumed they backed out this feature in that bug. But as you said there's a 2nd bug where they say this isn't resolved.

Maybe you can downgrade to Firefox 41 in the meantime? https://archive.mozilla.org/pub/mobile/releases/41.0.2/android-api-11/en-US/fennec-41.0.2.en-US.android-arm.apk

I'll let you know if they plan to push a fix before the next release on Dec. 14.

Noah_Sumo,

Thanks for the link. I had looked over the old releases folders on Mozilla, but wasn't sure how to go about nabbing FF41. The notes on the page about it are all, "Don't do that! Really, Don't Do That! Go to the Google Store and Get the Latest, or the Beta, Even! As we said, Don't do that! And here's a link, but Don't Do That!". Sure. Well, they scared me so much I just left Firefox uninstalled. Or maybe it was simply the lack of an instruction of "click on this link, and the process will start, you'll have to enable a side load, but (a) that'll pop up automatically, and (b) you can rig it, right there as an option in Android, for one time only, for this app, and it'll all work."

Your link worked: I have FF 41 installed and the battery life is back to normal, no trace of mdnsd. Once installed, I made a point of turning off auto update in FF41 and I can live with the occasional reminder from Android stating that I'm running an old version of Firefox.

But I rather think that this support chain should stay open until there's a reliable fix in the Beta, at least. Alternatively, and I have no idea if this is even possible, maybe FF 42 should be backed out of the Google Store and replace with FF41? I mean.. Battery life from 17-20 hours down to 4. That's double-plus ungood. :)

Gentlepeople:

The problem was recognized by the development team (https://bugzilla.mozilla.org/show_bug.cgi?id=1215012), has been beaten upon, and is now fixed.

Firefox for Android 42.0.2, currently available on the Google Play Store, does not have issues with the mdnsd and works like a champ. Thanks to all the people who have contributed to this.. And increased the stress so it got fixed before the next major release. (By the by: As discovered by the developers, it was in the next major release.. But no more. Beck123