Mac will no longer connect to any other machine on the network (via SMB/VNC)

[th0masp]

I have a Mac here that in the past without fail connected to every other machine (Mac/Win-PC/Linux-PC) on the network (via Samba through the Finder, same for VNC).

At some point it started to take longer than usual to connect and one day all of a sudden it wouldn't do it at all anymore. Still, if I click on a remote share of a sleeping server in Finder this action will wake up the remote machine so obviously some handshake at least must be getting through...?

Nothing has changed with the operating systems (no OS updates) nor network settings, router or network cabling. Every other computer can connect to this Mac's share just fine and I can still use ssh and sftp on the machine to reach the rest of the network. Interestingly ping times out when trying to reach a remote machine - on this Mac it only seems to work for the first hop on the network to the router (the other machines can ping this one though).

Any idea which places to look to solve this? And where would I find related error messages in the log files? I'm being drowned in output in the console but nothing stands out as an obvious candidate so far.

Thanks!

 

[BrianBaughn]

Did you try in a new, test user account on the Mac?

 

[th0masp]

Did you try in a new, test user account on the Mac?

I just tried this (with an admin level account):

Remote desktop/screen sharing to another Mac works for that user (and seems to have shaken something loose for my main user too - reentered my credentials and get a connection again!). Interesting!

No dice so far for the Samba shares though - same exact behaviour with the test account.

Which is that once you click on a share in the list there's a 'connection failed' message in the Finder's top left window corner. If I click on 'Connect as' next to the 'Screen sharing' button I get a popup saying that there's been an error when trying to connect with the server such-and-such (my translation - the interface isn't set to english).

 

[th0masp]

Ok, narrowed it down for SMB!

I have a firewall running that blocks outgoing traffic (called LuLu - similar to LittleSnitch). Seems I may have accidentally blocked some network daemon or the like at one point, probably when it popped up an alert. I'll just have to go through the (long! ) list of blocked applications and look for the culprit now.

Phew!