salt-minion tunnel initial connection

I have successfully set up a master and a minion using the Salt tutorial, between two hosted VPS (Debian 7).

I am trying to set-up a second minion on my laptop (Ubuntu 14.04), but following the same steps fails.

I am suspecting that my ISP is blocking some ports used by Salt. I ma be wrong but that wouldn't be the first time my problems are related to that (I have some wireless connection included in my housing contract and live in some kind of young worker residence).

Is there a way to tell which ports my ISP is blocking ?
Can I tunnel my salt minion connection through ssh ?

Note : ssh runs fine, if that can help, and I have access to remote servers (the other master and minion).

Anonymised command output below :

$ salt-minion -l debug
[DEBUG   ] Reading configuration from /etc/salt/minion
[DEBUG   ] Using cached minion ID from /etc/salt/minion_id: nha-Ub
[DEBUG   ] Configuration file path: /etc/salt/minion
[INFO    ] Setting up the Salt Minion "my_machine_name"
[DEBUG   ] Created pidfile: /var/run/salt-minion.pid
[DEBUG   ] Reading configuration from /etc/salt/minion
[DEBUG   ] Attempting to authenticate with the Salt Master at X.X.X.X
[DEBUG   ] Loaded minion key: /etc/salt/pki/minion/minion.pem
[ERROR   ] Attempt to authenticate with the salt master failed

Solution

I'd run a tcpdump on each side to see what packets are being sent and received, an example command for tcpdump:

tcpdump -i $INTERFACE -s 15000 -w testing.pcap

Where interface is eth0 etc.. (ifconfig) to confirm.

Then you can look at this in wireshark.

Another thing to look at is firewall, I'd put an allow rule in iptables for each WAN IP, just to make sure that's not causing any issues also.

By default, salt needs ports 4505 and 4506 open (TCP)