Help with Core Tunnel


Please, I'm new with core tunnel, I'm a little confused, how I can use it?, I want to use local port 8080, and the remote server want to use 161, how can use in app?

local IP : port 8080
remote server port 161

I want to redirect the SNMP query from my remote to my local pc.

Do you have any manual to understand better?


SSH port forwarding is a general proxying mechanism for TCP only, while SNMP is an UDP connection.

So you can't redirect SNMP queries over Core Tunnel directly, you need a bridge to transform UDP diagram into TCP diagram.

I found a guide that may help:

Let me know if you need assistance.



I have new version of core tunnel, suddenly stop working and won't open. how can solve this ?


Any crash log displayed? If not, what's the version of macOS? Are you using a M1 Mac? Is there any suspicious log item in ?


no open, no appear nothin, im using M1, where can get log?

I try to forward remote port 443 to local port 8080, I apply this rule

ssh -L localhost:8080: -o ServerAliveInterval=15 -o ServerAliveCountMax=3 -o ExitOnForwardFailure=yes administrator@

when try to open webpage in localhost didn't work

something is wrong?

Open, click Start button, type in "tunnel" in search bar, then launch Core Tunnel:


The correct command should be:

ssh -L localhost:8080:localhost:443 -o ServerAliveInterval=15 -o ServerAliveCountMax=3 -o ExitOnForwardFailure=yes administrator@

The second "localhost" means the local host name on remote


Did you enabled Menu bar icon mode in Preferences? Please check if this icon in your Menu bar:


I can't open windows, no load nothing, I restart my Mac but still happen the same.

Could you please run this command:

mv ~/Library/Containers/io.coressh.tunnel ~/Library/Containers/io.coressh.tunnel.bak

Then restart your Mac and relaunch Core Tunnel?


(base) ja@MBP-M1skyonesco ~ % mv ~/Library/Containers/io.coressh.tunnel ~/Library/Containers/io.coressh.tunnel.bak
mv: rename /Users/ja/Library/Containers/io.coressh.tunnel to /Users/ja/Library/Containers/io.coressh.tunnel.bak: No such file or directory

restart and same behavior :frowning:

Well, I think I've found the cause.

~/Library/Containers/io.coressh.tunnel should be created by system for Core Tunnel automatically, but for unknown reason, it didn't created as expected.

So when you try to rename the directory, it warns you it does not exists.

It should be a macOS fault. Do other newly installed apps work? Do you have installed third-party software like CleanMyMac or other protection/ cleaner tool?


Only use antivirus.

But no appear any events in my antivirus with core tunnel, this behavior happen in new version. old version works as normal

The container directory ~/Library/Containers/io.coressh.tunnel is managed by macOS, and the app (aka. Core Tunnel) has no privilege to rename or delete this folder.

Could you please give 3.0.1 beta a try? It has a different container folder named io.coressh.tunnel-beta.


Work ok this version beta, but what happen with official version ?

Have no idea about this glitch at this moment, but obviously it should be a macOS or third-party fault. The beta and official release have same codebase.

Please Quit Core Tunnel (Beta), and try again with this command:

cp -R ~/Library/Containers/io.coressh.tunnel-beta ~/Library/Containers/io.coressh.tunnel

Then restart your Mac again and relaunch Core Tunnel public release afterwards, it may be functional again.


The issue is with core tunnel, core shell work perfect!

Though it's highly unlikely an issue of the app, I'll keep an eye on it.