rthalley
macOS Tahoe does not provide dns configuration in /etc/resolv.conf
Describe the bug
On macOS Tahoe /etc/resolv.conf is not populated with dns server information anymore:
> cat /etc/resolv.conf
#
# macOS Notice
#
# This file is not consulted for DNS hostname resolution, address
# resolution, or the DNS query routing mechanism used by most
# processes on this system.
#
# To view the DNS configuration used by this system, use:
# scutil --dns
#
# SEE ALSO
# dns-sd(1), scutil(8)
#
# This file is automatically generated.
#
❯ scutil --dns
DNS configuration
resolver #1
search domain[0] : fritz.box
nameserver[0] : 192.168.10.1
nameserver[1] : fde2:c0d2:6cb1:0:62b5:8dff:fecc:bddf
nameserver[2] : 2a02:8109:b59e:7800:62b5:8dff:fecc:bddf
if_index : 14 (en0)
flags : Request A records, Request AAAA records
reach : 0x00020002 (Reachable,Directly Reachable Address)
resolver #2
domain : local
options : mdns
timeout : 5
flags : Request A records, Request AAAA records
reach : 0x00000000 (Not Reachable)
order : 300000
resolver #3
domain : 254.169.in-addr.arpa
options : mdns
timeout : 5
flags : Request A records, Request AAAA records
reach : 0x00000000 (Not Reachable)
order : 300200
resolver #4
domain : 8.e.f.ip6.arpa
options : mdns
timeout : 5
flags : Request A records, Request AAAA records
reach : 0x00000000 (Not Reachable)
order : 300400
resolver #5
domain : 9.e.f.ip6.arpa
options : mdns
timeout : 5
flags : Request A records, Request AAAA records
reach : 0x00000000 (Not Reachable)
order : 300600
resolver #6
domain : a.e.f.ip6.arpa
options : mdns
timeout : 5
flags : Request A records, Request AAAA records
reach : 0x00000000 (Not Reachable)
order : 300800
resolver #7
domain : b.e.f.ip6.arpa
options : mdns
timeout : 5
flags : Request A records, Request AAAA records
reach : 0x00000000 (Not Reachable)
order : 301000
resolver #8
domain : localhost
nameserver[0] : 127.0.0.1
port : 53
flags : Request A records, Request AAAA records
reach : 0x00030002 (Reachable,Local Address,Directly Reachable Address)
DNS configuration (for scoped queries)
resolver #1
search domain[0] : fritz.box
nameserver[0] : 192.168.10.1
nameserver[1] : fde2:c0d2:6cb1:0:62b5:8dff:fecc:bddf
nameserver[2] : 2a02:8109:b59e:7800:62b5:8dff:fecc:bddf
if_index : 14 (en0)
flags : Scoped, Request A records, Request AAAA records
reach : 0x00020002 (Reachable,Directly Reachable Address)
This means, that dnspython is not able to resolve name servers anymore.
⏎ ❯ python -c '
import dns.resolver
r = dns.resolver.Resolver()
print("Nameservers:", r.nameservers)
'
Traceback (most recent call last):
File "<string>", line 3, in <module>
r = dns.resolver.Resolver()
File "/Users/dwt/Code/Projekte/sntl/provisioning/.venv/lib/python3.13/site-packages/dns/resolver.py", line 953, in __init__
self.read_resolv_conf(filename)
~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
File "/Users/dwt/Code/Projekte/sntl/provisioning/.venv/lib/python3.13/site-packages/dns/resolver.py", line 1047, in read_resolv_conf
raise NoResolverConfiguration("no nameservers")
dns.resolver.NoResolverConfiguration: no nameservers
Context (please complete the following information):
- dnspython version [e.g. 2.2.1]
- Python version [e.g. 3.10.0]
❯ uv pip list | grep dnspython
Using Python 3.13.4 environment at: /Users/dwt/Code/Projekte/sntl/provisioning/.venv
dnspython 2.8.0
- OS: [e.g. macOS Monterey]
❯ sw_vers
ProductName: macOS
ProductVersion: 26.1
BuildVersion: 25B78
Considered Workarounds
Probably I will manually add dns config to /etc/resolv.conf but macOS will regenerate that file periodically, at least with system updates, so this is not a good setup. Furthermore, this means that every user will have to manually update that file when they reconfigure their system or roam between different networks with different name servers.
It's populated for me. I get the same comment you do about it not being used by macOS, but then it has a nameserver entry and a search list, as received from my DHCP server.
It auto-generates if I set a local nameserver, and it also auto-regenerates if I clear it (in that case it falls back to what DHCP says)
I see generation on other Tahoe machines, so my sense is that the file, while not used by macOS itself, is still meant to be generated and populated for legacy software. So I'm wondering rather why it isn't generating for you!
Indeed, this seems to have been fixed on my system after some time has passed. Not quite sure why. Sorry for the bother.