mDNS resolution and avahi browsing stop working after some time

Hi, I have a weird problem with mDNS name resolution and avahi browsing.

When my system connects to the wifi, everything works as expected. Trying to reach hosts on .local (e.g., foo.local) works and avahi-browse -a returns results about all I have on the lan.

After some time (probably after a suspend-resume cycle where the system remains suspended for enough time), all that is related to avahi/mDNS stops working. The machine keeps being online (I can reach other hosts and hosts on the internet), but mDNS name resolution returns nothing and so does avahi-browse -a.

Disconnecting and reconnecting the wifi to the same AP, is enough to restore the broken functionality.
Any idea? How can I check if my system gets the multicast packets that the other hosts use to advertise their presence?

Please try to search the forum for “local” or “dns” or “hosts”

Provide Information:

As mentioned, everything works… for some time. The problem seems to be the intel wifi (Intel Corporation Centrino Wireless-N 2230 - rev c4) that after some time of inactivity stops listening to incoming packets altogether (in many occasions I cannot even ping the machine from the outside).

Resuming operation from the host (e.g. pinging to the outside from the host) seems to wake up the card, but it takes some time before it receives the avahi broadcasts from the other hosts on the net.
Adding a cheap usb wifi dongle to the system and using that seems to fix the issue.

Any idea of why the intel wifi should do this?

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Hi, I’m having the same issue on my Acer Nitro 5 (AN515-42) with Qualcomm Atheros QCA6174, I had been looking for an explanation on why my printer was not found after a couple minutes working. I checked and noted that

avahi-browse --all --ignore-local --resolve --terminate

returned nothing, but after disabling and re-enabling wifi it displays my printer services again (for a while).

What is the reason behind this behavior? How can we find out what is happening with avahi/network card?

In my case, I think the issue is with the internal wifi card (an Intel Centrino Wireless-N 2230 - rev c4). After having bought a usb wifi dongle, as long as I rely only on that the issue seems to be gone.

The issue is possibly with the iwlfifi driver not working well for that Intel card or getting stuck in power save states. Do you also have an intel wifi card?

Working with an external wifi dongle in my case has additional advantages like support for 5GHz bands. What is extremely unfortunate is that Network Manager works very poorly with two wifi cards. There is an open issue, but it seems not to catch much interest (see Using rfkill on one network card disables wireless entirely (#76) · Issues · NetworkManager / NetworkManager).

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It’s my internal wifi card but it is not an Intel Centrino, it’s Qualcomm Atheros and it does not seems to be in power saving mode…
But it is quite consistent an it affects KDE connect, too, for example…
Maybe it deserves a new thread?

I think that a quick test would be to try with a USB dongle and see if something changes. Because with network manager it will not be possible to disable the internal card, you should manually make sure that you initially connect with the dongle. If the wifi temporarily goes down, you’ll need to check again that the connection used the USB dongle. It is a bit of a burden, but you’ll be able to check if the problem is specific of your internal card.

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