ZeroTrust - Unable to connect - Port 53 Bound

Hi, Couldflare Warp is not working on my Mac OS M1 (arm64) with Ventura 13.2.1

The following error message appears: Unable to connect - Port 53 Bound

So far I have tried the stable and beta versions of WARP but none works. Do you know how to get it working? Any guidance to debug or solve the issue?

Thanks,

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Greetings, I am getting an error when trying to connect via Warp Zero Trust.
So far I have tried using the latest version of the Mac OS app on MacOS Ventura 13.2.1, and downloading the beta version. But connecting does not work.

I also tried the following command:
$ lsof -i TCP:53 $

Could you please provide guidance to get the app working?

Hello everyone, any updates? Is there a way to contact Cloudflare support about this?

By posting here, you already have. It may take some time to receive a response.

You can also try the Cloudflare Developers Discord.

Thanks @epic.network for the update

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The issue was caused by a Bonjour service binding to port 53 when sharing resources was * enabled. Perhaps as a recommendation it would be great if Cloudflare improves documentation on requirements such as ports required for this app to work. And how to troubleshoot issues. The exact process was ‘_mdnsresponder’ in case it helps anyone. Thanks

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Hi @arturo I’m also facing the same issue. Any advice on how to fix this?
I couldn’t stop the mdnsresponder as System Integrity Protection is enabled in my mac.

Just disable internet sharing, and that stops mDNSResponder from binding on port 53

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Hi @mehdinaraghi2015 thanks for the response. Internet sharing is already disabled in my mac.
How can I stop mDNSResponder from binding on port 53?
I tried to disable it but couldn’t do due to system integrity protection enabled. Please advise.

Note: I’m connected to internet via my mobile hotspot.

➜  ~ sudo lsof -iTCP:53 -iUDP:53 -n -P
COMMAND     PID           USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
mDNSRespo 11539 _mdnsresponder   19u  IPv4 0x399fc225f8277397      0t0  UDP *:53
mDNSRespo 11539 _mdnsresponder   20u  IPv6 0x399fc225f82786b7      0t0  UDP *:53
mDNSRespo 11539 _mdnsresponder   21u  IPv4 0x399fc22ac51a4dbf      0t0  TCP *:53 (LISTEN)
mDNSRespo 11539 _mdnsresponder   22u  IPv6 0x399fc21c5ce2c247      0t0  TCP *:53 (LISTEN)
➜  ~
➜  ~ sudo launchctl stop -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
➜  ~
➜  ~ sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
/System/Library/LaunchDaemons/com.apple.mDNSResponder.plist: Operation not permitted while System Integrity Protection is engaged
Unload failed: 150: Operation not permitted while System Integrity Protection is engaged
➜  ~
➜  ~ sudo lsof -iTCP:53 -iUDP:53 -n -P
COMMAND     PID           USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
mDNSRespo 11539 _mdnsresponder   19u  IPv4 0x399fc225f8277397      0t0  UDP *:53
mDNSRespo 11539 _mdnsresponder   20u  IPv6 0x399fc225f82786b7      0t0  UDP *:53
mDNSRespo 11539 _mdnsresponder   21u  IPv4 0x399fc22ac51a4dbf      0t0  TCP *:53 (LISTEN)
mDNSRespo 11539 _mdnsresponder   22u  IPv6 0x399fc21c5ce2c247      0t0  TCP *:53 (LISTEN)

@kannanaut that’s an interesting one. Try disabling everything in ‘Sharing’ and then:

sudo killall -HUP mDNSResponder

If you have docker or another virtualization software running, try to exit it.
ps ax|grep -i docker|egrep -iv 'grep|com.docker.vmnetd'|awk '{print $1}'|xargs kill

then, try:
sudo netstat -vanp tcp | grep ".53 "
netstat -vanp tcp | grep ".53 " | awk '{print $9}' | xargs ps -p

Still no luck :frowning:
I suspect this error has something to do with using mobile hotspot for internet. Because I didn’t encounter this so far when I used wifi.

➜  ~ sudo killall -HUP mDNSResponder
Password:
➜  ~
➜  ~ ps ax|grep -i docker|egrep -iv 'grep|com.docker.vmnetd'|awk '{print $1}'|xargs kill

➜  ~ sudo netstat -vanp tcp | grep ".53 "
tcp6       0    394  2409:40f4:1037:e.49353 2600:9000:229f:d.443   FIN_WAIT_1   131072  131672  98154      0 0013b 00000000 000000000022478c 00000080 00000800      0      0 000001
tcp4       0    719  192.168.24.90.49282    3.7.13.58.443          FIN_WAIT_1   131072  131072  99012      0 0013b 00000008 0000000000223c53 00000081 00000900      0      0 000001
tcp6       0      0  *.53                   *.*                    LISTEN       131072  131072  52885      0 00100 00000006 000000000017634e 00000000 00000800      1      0 000001
tcp4       0      0  *.53                   *.*                    LISTEN       131072  131072  52885      0 00100 00000006 000000000017634d 00000000 00000900      1      0 000001
➜  ~ netstat -vanp tcp | grep ".53 " | awk '{print $9}' | xargs ps -p
  PID TTY           TIME CMD
52885 ??         1:31.24 /usr/sbin/mDNSResponder
98154 ??         7:11.02 /Applications/Firefox.app/Contents/MacOS/firefox
99012 ??         0:06.65 /Applications/Slack.app/Contents/Frameworks/Slack Helper.app/Contents/MacOS/Slack Helper --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-GB --service-sandbox-type=
➜  ~ sudo lsof -iTCP:53 -iUDP:53 -n -P
COMMAND     PID           USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
mDNSRespo 52885 _mdnsresponder   19u  IPv4 0x399fc225f679fd27      0t0  UDP *:53
mDNSRespo 52885 _mdnsresponder   21u  IPv6 0x399fc225f67a0057      0t0  UDP *:53
mDNSRespo 52885 _mdnsresponder   22u  IPv4 0x399fc22ac58102af      0t0  TCP *:53 (LISTEN)
mDNSRespo 52885 _mdnsresponder   23u  IPv6 0x399fc21c5ce28dc7      0t0  TCP *:53 (LISTEN)
➜  ~ sudo killall -HUP mDNSResponder
➜  ~ sudo lsof -iTCP:53 -iUDP:53 -n -P
COMMAND     PID           USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
mDNSRespo 52885 _mdnsresponder   19u  IPv4 0x399fc225f679fd27      0t0  UDP *:53
mDNSRespo 52885 _mdnsresponder   21u  IPv6 0x399fc225f67a0057      0t0  UDP *:53
mDNSRespo 52885 _mdnsresponder   22u  IPv4 0x399fc22ac58102af      0t0  TCP *:53 (LISTEN)
mDNSRespo 52885 _mdnsresponder   23u  IPv6 0x399fc21c5ce28dc7      0t0  TCP *:53 (LISTEN)

I can connect while using personal hotspot. It could be different in your case.

Check /etc/resolv.conf and /etc/resolver/ if it exists, look for /etc/resolver/multicast and see if it mentions any ports.
Lastly, /Library/Preferences/com.apple.mDNSResponder.plist

If those don’t give any clues, then I don’t know. Try disabling your launch agents and services (especially virtualization software) and try to pinpoint the cause

Run command:
sudo /usr/bin/sudo /usr/bin/defaults write /Library/Preferences/com.apple.mDNSResponder.plist NoMulticastAdvertisements -bool true and reboot can fix issue