So first of all thank you for sticking with me on this. This is definitely an education....... And quickly becoming an obsession.
I installed the gufw and set it to allow incoming and outgoing. So in theory my computers firewall should be fine.

I'm going to write down the settings on my apple router and if you see anything weird can you please tell me.

The router is an AirPort Extreme
There is an option to 'allow set up over WAN which I don't have selected.
I'm connecting using DHCP
there is a subnet mask, an IPv4 address and a router address. ( what is a router address for?)

Router mode is - DHCP and NAT
DHCP range
DHCP reservations has nothing in it. It's blank.
Enable access control is unchecked ( when I check this it opens up a time limit to log in called timed access control)

Port settings
Description - remote login - ssh
Public TCP ports - 22
Private IP address - 10. Etc
Private TCP ports - 22
Firewall entry type - IPv4 port mapping (but it's greyed out)

Network options
DCHP lease - 1 day
IPv4 range 10. To 200
Enable NAT port mapping protocol is enabled
Enable default host at .... Is not checked

So these are the settings on the apple router. Is there anything weird that you can see on it?
Thanks guys

Btw. Both My musician friend in the UK and myself are using ubuntu studio.

Great! At least we have that out of the way. One less thing to worry about...

Good, you don't need to enable that; it's really only useful if you were to trying to remotely connect to a Time Capsule (Airport Extreme w/integrated hard drive) or an external hard drive connected to a regular AE back at your house etc.

The router address is the actual "gateway" address your AE uses with the ISP.

Again, these settings look OK. The only potential issue with not having a DHCP reservation for your laptop's Wifi adapter is that it may change over time--and if it does, the rule you configure to forward the SSH traffic will break, since it's no longer connecting to the correct IP address.
(For the time being, though, let's just see if we can get this functional, even just initially! )

Looks good here, provided the Private IP Address field contains the correct IP of your intended laptop (to verify: at a terminal on the laptop type "ifconfig wlan0" -- just to make sure nothing has changed there...)

Again, I can't find any issues here.

The other possibility, then, is that your ISP may very well be blocking port 22 traffic (it happens).
To overcome this, you would need to try changing the incoming rule for port forwarding to receive it on a different port, and your friend in the UK will have to change the port he attempts to connect to your box to the same.

For instance, let's say you want to try TCP (not UDP) 222 instead of 22. In that case, return to the ACU and modify your existing "Remote Login - SSH" rule so that the Public TCP Ports is changed to 222. However, do NOT change the Private TCP ports setting--only the Public one, as your local laptop is still waiting to hear on the original port.

Once you've updated the rule and the AE applies the settings, your mate in Blighty would specify using port 222 instead of 22 on whatever client he's using when attempting to connect to your computer. If he's using a terminal in Ubuntu Studio then he would type "ssh -p 222 your.public.ip.address" to try connecting again.

Hopefully this makes sense? If not, let us know...


strick

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i reversed the situation and tried to log into his account in the uk. i got this. what does it mean
ssh: connect to host 192.168.1.91 port 22: No route to host

The 192. network is a private one; it's nonroutable, so you can't just ssh to his private address.

He would need to set up things similarly on his end i.e. open his router and/or firewall to accept incoming SSH traffic on tcp/22, have it port-forwarded to his computer, and then you would try to connect to his computer not using his private 192.x address but, instead, his public one i.e. 5.57.x.x or whatever.

Wrong type of address, that would be local to the router. You need another you may be able to use I think it was whatsmyip.

is there a website that will test my incoming only? that way i wouldnt have to concern myself with his set up and at least find out if my router is allowing access to my persona;l ip

my isp didnt know if they were blocking port 22

im going to change my port to 222 and see if that works. the guy at the isp said he didnt know if they were blocking port 22. its worth a try

what is a website i can use to try and trace my ip and see whaere the trail ends?

As EDDY1 said, you could try https://www.whatismyip.com/ ; that will tell you what your "public" IP address is -- and should be the one your friend is using to ssh to you.

FYI all - this is basically the same thread as the other one he created:
http://www.linuxquestions.org/questi...nd-4175540869/

At this point both threads are addressing the same problem. Merging them is probably a better idea than keeping them separate.

I hadn't seen that thread -- thanks

Are we sure the ssh daemon is running on this target laptop? That's a biggie.

ok guys, i just had a huge breakthrough.
i changed the incoming port to 222 and i did a search on canyouseeme.org and for the first time I got SUCCESS!!!!!!!!!
my troubleshooting is not over but at least i have discovered that port 22 was blocked by my isp. when i type in port 22 it comes up as an error.

i have sent an email off to my friend in the uk so he can change his port to 222 and ill see if we can log in after that.
phew! this linux network ssh thing is some deep stuff.
i thank all of you for your selfless support. i will write as soon as i get in to the next batch of tests which hopefully will end in success.

one quick question.... if i have an account on my computer for him, in order for him to connect to his account on my computer he types friend@my.public.ip.address and then the password i gave him.

is this correct? because i dont want to make a mistake this far down the road. I believe thats what it is but can someone confirm it please. thank you.

Awesome update! Glad to hear you're making some progress!!

Yes, that's correct: at a linux terminal he would type

Don't let him forget that part that includes specifying a port other than the default, or he definitely won't be able to reach you.

The other possibility, then, is that your ISP may very well be blocking port 22 traffic (it happens).
To overcome this, you would need to try changing the incoming rule for port forwarding to receive it on a different port, and your friend in the UK will have to change the port he attempts to connect to your box to the same.

strick did tell me!!!!!!!

FYI - You should probably not be using port 222. Ports 0-1023 are reserved for system services, and there's a pretty high chance of running into conflicts if you pick something in that range. User ports should be 1024 or higher. You can go all the way up to 65535, so there is plenty of room to pick something unique.

The funny thing is, very little of what you've been dealing with here has anything at all to do with Linux. You'd be running into the exact same set of issues if you were trying to expose literally any service to the web (FTP, HTTP, etc.), whether your server was running Linux, Windows, OS/X, or anything else.

All of the internal/external private/public IP confusion and port forwarding business is completely independent of what operating system you're using or what service you're trying to make public. The only Linux/SSH specific part of this setup has been which port you were trying to make public (SSH is 22, FTP is 21, HTTP is 80, and so on), and making sure your sshd daemon was running, which it has been from the start.

For example, say you wanted to allow remote desktop access to your Windows computer from outside your local network. Remote desktop uses port 3389, so you'd have to go into your router and add a new port forwarding rule to push any incoming connections on port 3389 to your Windows computer's private IP, and then from outside your network you would use a remote desktop client to connect to your public IP. You may run into ISP filtering there too, in which case you'd need to pick your own custom port, modify the port forwarding rule, etc.

Welcome to the wonderful world of computer networking

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