mDNS not working for Raspberry Pi Zero W

Question

So, I've just got a Raspberry Pi Zero W and installed Raspbian Stretch Lite (headless Debian Stretch). I was able to configure WiFi in headless mode and the Raspberry connected to my home WiFi network.

I've then run nmap 192.168.100.0/24 -p 22 to find out the device's IP:

Starting Nmap 7.70 ( https://nmap.org ) at 2019-06-07 22:01 +03

Nmap scan report for 192.168.100.57
Host is up (0.0095s latency).

PORT   STATE SERVICE
22/tcp open  ssh

Nmap done: 256 IP addresses (5 hosts up) scanned in 2.76 seconds

Looks like 192.168.100.57 is the droid I am looking for. Connecting over SSH works:

ssh [email protected]
Linux raspberrypi-1 4.14.98+ #1200 Tue Feb 12 20:11:02 GMT 2019 armv6l

pi@raspberrypi-1:~ $ hostname
raspberrypi-1

I've already played a little with it and changed the hostname to raspberrypi-1, but everything I'm asking happened with the default name too (raspberrypi).

Avahi is running on my Raspberry:

pi@raspberrypi-1:~ $ ps axu | grep avahi
avahi      247  0.0  0.7   6384  3168 ?        Ss   17:54   0:00 avahi-daemon: running [raspberrypi-1.local]
avahi      255  0.0  0.3   6384  1480 ?        S    17:54   0:00 avahi-daemon: chroot helper
pi         829  0.0  0.4   4360  2028 pts/0    S+   19:10   0:00 grep --color=auto avahi

Self ping by raspberrypi-1.local name works too:

pi@raspberrypi-1:~ $ ping raspberrypi-1.local
PING raspberrypi-1.local (192.168.100.57) 56(84) bytes of data.
64 bytes from 192.168.100.57 (192.168.100.57): icmp_seq=1 ttl=64 time=0.230 ms
^C
--- raspberrypi-1.local ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms

Now, I'm trying to connect to Pi by it's hostname from my laptop:

$ ssh [email protected]                                                                                                                                                         
ssh: Could not resolve hostname raspberrypi-1.local: Name or service not known

But avahi-resolve is able to resolve that name!

$ avahi-resolve -nv raspberrypi-1.local                                                                                                                                                   
Server version: avahi 0.7; Host name: millennium-falcon.local
raspberrypi-1.local     192.168.100.57

However, avahi-browse -arp does not show my Pi.

My laptop's /etc/nsswitch.conf is:

passwd: files mymachines systemd
group: files mymachines systemd
shadow: files

publickey: files

hosts: files mymachines mdns4_minimal [NOTFOUND=return] resolve [!UNAVAIL=return] dns mdns4 myhostname
networks: files

protocols: files
services: files
ethers: files
rpc: files

netgroup: files

And /etc/resolv.conf is:

nameserver fe80::1%wlp2s0
nameserver 82.209.240.241
nameserver 82.209.243.241

I cannot understand what's wrong with my config and why cannot I connect to the Pi using its hostname. WAIDW?

Answer 1

The issues seems to be gone after creating a /etc/mdns.allow file on my laptop:

$ ll /etc/mdns.allow                                                                                                                                                                      
-rw-r--r-- 1 root root 15 Jun  7 23:56 /etc/mdns.allow
$ cat /etc/mdns.allow                                                                                                                                                                     
.local.
.local

I found the solution here. Still not sure why it doesn't work by default…