i have to create a virtual topology with miniedit that has to talk using the mqtt sub/pub system.
i'm working on virtualbox (mininet-wifi)
i have installed mosquitto & the clients... using the terminals i have no problem with:
mosquitto_sub -t test
mosquitto_pub -t test -m hello!
but when i emulate the topology on Miniedit with (controller,switch and two hosts), the hosts cannot talk using mosquitto, i think that there is no broker that can handle the communications in the virtual topology, any suggestions?
I tried to connect also to a remote server, using cloudmqtt but i only got failed connection
i expect that using
xterm h1 h2
on the Comand Line Interface of miniedit, i would be capable of make the two hosts talks beetween them using
mosquitto_sub/pub system, because also in the xterm of the host, if i type
service mosquitto status
i obtain that
mosquitto is active
UPDATE
solved.
i just have to run another host in which i type "mosquitto" and the others hosts would just reach it using "mosquitto_sub/pub - h 10.0.0.3 for example
2 brokers (1 on each hosts) won't automatically discover each other when the "link" comes up.
You will have to either manually configure the a bridge between the 2 brokers if you want messages to be shared.
Or pick one and have the clients explicitly connect to that one broker. e.g. the -h option for the mosquitto_pub or mosquitto_sub commands.
I agree with the solution. Let me give more in depth explanation.
Run basic mininet topo with 4 hosts and 4 switches.
mn --topo linear,4
Then open xterm for 3 hosts
xterm h1 h2 h3
Three terminals will pop up. One of them will be the host. on h3's(10.0.0.3) xterm terminal run
mosquitto
On h2(10.0.0.2) subscribe to the topic with;
mosquitto_sub -h 10.0.0.3 -t "home/bedroom/light"
On h1(10.0.0.1) publish a message by;
mosquitto_pub -h 10.0.0.3 -t "home/bedroom/light" -m "ON"
You can now see the message on h2's terminal. Hope it helps.
I am running a switch test Switch Test on real environment with one openvswitch and real sdn switch.
I created a bridge on openvswitch and added ports (ex. eth0, eht1). But I want to know logical port numbers (like 1, 2) which command gives me correct information. ovs-ofctl show bridge s1 shows
1(eth3): mac address etc
2(eth4):
5(eth5):
and ovs-dpctl show
port 2: eth3
port 3: eth4
port 4: eth5
But results are not showing proper mapping of physical to logical ports. Observer eth5 in both cases for ofctl it gives 5 and for dpctl it gives 4. Is there any way to get correct port id's.
I personally feel both these commands are not giving correct port ids. To isolate this scenario. On Mininet I created 2 openvswitchs and run dpctl command as above it gives me 1,2,3,4,5,6 as port numbers but I am not able to run the test with these port numbers. For both switches I used 1,2,3 test executes successfully. What I mean it, if I give 1,2,3 port numbers for one switch and 4,5,6 for another switch tests doesn't execute. Any help is much appreciated.
you can use to show ofport
sudo ovs-vsctl -- --columns=name,ofport list Interface
You can use this command to specify the ofport of the port you are adding in the bridge:
ovs-vsctl add-port br0 eth0 -- set Interface eth0 ofport=1
i think you can try ovs-vsctl list Interface
I currently have my Raspberry pi setup with network connectivity and i can connect to it via local ip addres like this:
192.168.0.x
Is there anyway i use my puplic ip to ssh into my raspberry pi ?
I think a Dynamic DNS is usualy the way to go. I use FreeDNS and I think it's pretty good. Instructions for setup by dentaku65:
First of all register your account on Freedns. Freedns offers a bunch of domain names, from my taste the best ones (or the ones easy to remember) are:
mooo.com
ignorelist.com
Assume that you register: your_host>.ignorelist.com
Install inadyn:
sudo apt-get install inadyn curl
Open the url: http://freedns.afraid.org/dynamic/
Login with your account
Select the link Direct URL beside .ignorelist.com
Copy everything from the right of the ? in the address bar (alphanumeric string)
Create configuration file of inadyn:
sudo gedit /etc/inadyn.conf
And save this content:
--username <your_username>
--password <your_password>
--update_period 60000
--forced_update_period 320000
--alias <your_host>.ignorelist.com,alphanumeric string
--background
--dyndns_system default#freedns.afraid.org
--syslog
Add inadyn to crontab:
export EDITOR=gedit && sudo crontab -e
Edit the file to add the following line:
#reboot /usr/sbin/inadyn
Reboot your PC
Wait 3 minutes
Check if inadyn is running:
ps -A | grep inadyn
Check inadyn behaviour:
more /var/log/messages |grep INADYN
Check if your host is up:
ping <your_host>.ignorelist.com
There are two possible solutions to this problem.
If your ISP provides public ip, you can use dynamic DNS services from no-ip or dyndns or any other equivalent service providers and you can forward port #22 to rpi ip using your router menu.
If your ISP doesn't provide public ip and you are behind NAT. You can make use of reverse remote ssh method mentioned in this link. But to access via this method, you need a server in between that's having a public ip. http://www.tunnelsup.com/raspberry-pi-phoning-home-using-a-reverse-remote-ssh-tunnel
Hope it helps.
you may need to enable portfowarding on your router
By default, google refine listens on port 3333. How does one start it on a different port?
[There some other process that has taken up 3333 and I cannot change that]
Update: Running this on a Mac (10.8.x)
$ ./refine -p 9999
From the documentation: https://github.com/OpenRefine/OpenRefine/wiki/FAQ
You can specify a different port on the command line.
./refine -p <port>
If you edit /Applications/Google Refine.app/Contents/Info.plist
and replace
<string>-Xms256M -Xmx4096M -Drefine.version=r2407</string>
with
<string>-Xms256M -Xmx4096M -Drefine.version=r2407 -Drefine.port=5555</string>
(or whatever port number you need instead of 5555) this should work.
Adapted from the bottom of the OpenRefine instructions page: https://github.com/OpenRefine/OpenRefine/wiki/Installation-Instructions
When connecting to remote hosts via ssh, I frequently want to bring a file on that system to the local system for viewing or processing. Is there a way to copy the file over without (a) opening a new terminal/pausing the ssh session (b) authenticating again to either the local or remote hosts which works (c) even when one or both of the hosts is behind a NAT router?
The goal is to take advantage of as much of the current state as possible: that there is a connection between the two machines, that I'm authenticated on both, that I'm in the working directory of the file---so I don't have to open another terminal and copy and paste the remote host and path in, which is what I do now. The best solution also wouldn't require any setup before the session began, but if the setup was a one-time or able to be automated, than that's perfectly acceptable.
zssh (a ZMODEM wrapper over openssh) does exactly what you want.
Install zssh and use it instead of openssh (which I assume that you normally use)
You'll have to have the lrzsz package installed on both systems.
Then, to transfer a file zyxel.png from remote to local host:
antti#local:~$ zssh remote
Press ^# (C-Space) to enter file transfer mode, then ? for help
...
antti#remote:~$ sz zyxel.png
**B00000000000000
^#
zssh > rz
Receiving: zyxel.png
Bytes received: 104036/ 104036 BPS:16059729
Transfer complete
antti#remote:~$
Uploading goes similarly, except that you just switch rz(1) and sz(1).
Putty users can try Le Putty, which has similar functionality.
On a linux box I use the ssh-agent and sshfs. You need to setup the sshd to accept connections with key pairs. Then you use ssh-add to add you key to the ssh-agent so you don't have type your password everytime. Be sure to use -t seconds, so the key doesn't stay loaded forever.
ssh-add -t 3600 /home/user/.ssh/ssh_dsa
After that,
sshfs hostname:/ /PathToMountTo/
will mount the server file system on your machine so you have access to it.
Personally, I wrote a small bash script that add my key and mount the servers I use the most, so when I start to work I just have to launch the script and type my passphrase.
Using some little known and rarely used features of the openssh
implementation you can accomplish precisely what you want!
takes advantage of the current state
can use the working directory where you are
does not require any tunneling setup before the session begins
does not require opening a separate terminal or connection
can be used as a one-time deal in an interactive session or can be used as part of an automated session
You should only type what is at each of the local>, remote>, and
ssh> prompts in the examples below.
local> ssh username#remote
remote> ~C
ssh> -L6666:localhost:6666
remote> nc -l 6666 < /etc/passwd
remote> ~^Z
[suspend ssh]
[1]+ Stopped ssh username#remote
local> (sleep 1; nc localhost 6666 > /tmp/file) & fg
[2] 17357
ssh username#remote
remote> exit
[2]- Done ( sleep 1; nc localhost 6666 > /tmp/file )
local> cat /tmp/file
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
...
Or, more often you want to go the other direction, for example if you
want to do something like transfer your ~/.ssh/id_rsa.pub file from
your local machine to the ~/.ssh/authorized_keys file of the remote
machine.
local> ssh username#remote
remote> ~C
ssh> -R5555:localhost:5555
remote> ~^Z
[suspend ssh]
[1]+ Stopped ssh username#remote
local> nc -l 5555 < ~/.ssh/id_rsa.pub &
[2] 26607
local> fg
ssh username#remote
remote> nc localhost 5555 >> ~/.ssh/authorized_keys
remote> cat ~/.ssh/authorized_keys
ssh-rsa AAAAB3NzaC1yc2ZQQQQBIwAAAQEAsgaVp8mnWVvpGKhfgwHTuOObyfYSe8iFvksH6BGWfMgy8poM2+5sTL6FHI7k0MXmfd7p4rzOL2R4q9yjG+Hl2PShjkjAVb32Ss5ZZ3BxHpk30+0HackAHVqPEJERvZvqC3W2s4aKU7ae4WaG1OqZHI1dGiJPJ1IgFF5bWbQl8CP9kZNAHg0NJZUCnJ73udZRYEWm5MEdTIz0+Q5tClzxvXtV4lZBo36Jo4vijKVEJ06MZu+e2WnCOqsfdayY7laiT0t/UsulLNJ1wT+Euejl+3Vft7N1/nWptJn3c4y83c4oHIrsLDTIiVvPjAj5JTkyH1EA2pIOxsKOjmg2Maz7Pw== username#local
A little bit of explanation is in order.
The first step is to open a LocalForward; if you don't already have
one established then you can use the ~C escape character to open an
ssh command line which will give you the following commands:
remote> ~C
ssh> help
Commands:
-L[bind_address:]port:host:hostport Request local forward
-R[bind_address:]port:host:hostport Request remote forward
-D[bind_address:]port Request dynamic forward
-KR[bind_address:]port Cancel remote forward
In this example I establish a LocalForward on port 6666 of localhost
for both the client and the server; the port number can be any
arbitrary open port.
The nc command is from the netcat package; it is described as the
"TCP/IP swiss army knife"; it is a simple, yet very flexible and
useful program. Make it a standard part of your unix toolbelt.
At this point nc is listening on port 6666 and waiting for another
program to connect to that port so it can send the contents of
/etc/passwd.
Next we make use of another escape character ~^Z which is tilde
followed by control-Z. This temporarily suspends the ssh process and
drops us back into our shell.
One back on the local system you can use nc to connect to the
forwarded port 6666. Note the lack of a -l in this case because that
option tells nc to listen on a port as if it were a server which is
not what we want; instead we want to just use nc as a client to
connect to the already listening nc on the remote side.
The rest of the magic around the nc command is required because if
you recall above I said that the ssh process was temporarily
suspended, so the & will put the whole (sleep + nc) expression
into the background and the sleep gives you enough time for ssh to
return to the foreground with fg.
In the second example the idea is basically the same except we set up
a tunnel going the other direction using -R instead of -L so that
we establish a RemoteForward. And then on the local side is where
you want to use the -l argument to nc.
The escape character by default is ~ but you can change that with:
-e escape_char
Sets the escape character for sessions with a pty (default: ‘~’). The escape character is only recognized at the beginning of a line. The escape character followed by a dot
(‘.’) closes the connection; followed by control-Z suspends the connection; and followed by itself sends the escape character once. Setting the character to “none” disables any
escapes and makes the session fully transparent.
A full explanation of the commands available with the escape characters is available in the ssh manpage
ESCAPE CHARACTERS
When a pseudo-terminal has been requested, ssh supports a number of functions through the use of an escape character.
A single tilde character can be sent as ~~ or by following the tilde by a character other than those described below. The escape character must always follow a newline to be interpreted
as special. The escape character can be changed in configuration files using the EscapeChar configuration directive or on the command line by the -e option.
The supported escapes (assuming the default ‘~’) are:
~. Disconnect.
~^Z Background ssh.
~# List forwarded connections.
~& Background ssh at logout when waiting for forwarded connection / X11 sessions to terminate.
~? Display a list of escape characters.
~B Send a BREAK to the remote system (only useful for SSH protocol version 2 and if the peer supports it).
~C Open command line. Currently this allows the addition of port forwardings using the -L, -R and -D options (see above). It also allows the cancellation of existing remote port-
forwardings using -KR[bind_address:]port. !command allows the user to execute a local command if the PermitLocalCommand option is enabled in ssh_config(5). Basic help is avail‐
able, using the -h option.
~R Request rekeying of the connection (only useful for SSH protocol version 2 and if the peer supports it).
Using ControlMaster (the -M switch) is the best solution, way simpler and easier than the rest of the answers here. It allows you to share a single connection among multiple sessions. Sounds like it does what the poster wants. You still have to type the scp or sftp command line though. Try it. I use it for all of my sshing.
In order to do this I have my home router set up to forward port 22 back to my home machine (which is firewalled to only accept ssh connections from my work machine) and I also have an account set up with DynDNS to provide Dynamic DNS that will resolve to my home IP automatically.
Then when I ssh into my work computer, the first thing I do is run a script that starts an ssh-agent (if your server doesn't do that automatically). The script I run is:
#!/bin/bash
ssh-agent sh -c 'ssh-add < /dev/null && bash'
It asks for my ssh key passphrase so that I don't have to type it in every time. You don't need that step if you use an ssh key without a passphrase.
For the rest of the session, sending files back to your home machine is as simple as
scp file_to_send.txt your.domain.name:~/
Here is a hack called ssh-xfer which addresses the exact problem, but requires patching OpenSSH, which is a nonstarter as far as I'm concerned.
Here is my preferred solution to this problem. Set up a reverse ssh tunnel upon creating the ssh session. This is made easy by two bash function: grabfrom() needs to be defined on the local host, while grab() should be defined on the remote host. You can add any other ssh variables you use (e.g. -X or -Y) as you see fit.
function grabfrom() { ssh -R 2202:127.0.0.1:22 ${#}; };
function grab() { scp -P 2202 $# localuser#127.0.0.1:~; };
Usage:
localhost% grabfrom remoteuser#remotehost
password: <remote password goes here>
remotehost% grab somefile1 somefile2 *.txt
password: <local password goes here>
Positives:
It works without special software on either host beyond OpenSSH
It works when local host is behind a NAT router
It can be implemented as a pair of two one-line bash function
Negatives:
It uses a fixed port number so:
won't work with multiple connections to remote host
might conflict with a process using that port on the remote host
It requires localhost accept ssh connections
It requires a special command on initiation the session
It doesn't implicitly handle authentication to the localhost
It doesn't allow one to specify the destination directory on localhost
If you grab from multiple localhosts to the same remote host, ssh won't like the keys changing
Future work:
This is still pretty kludgy. Obviously, it would be possible to handle the authentication issue by setting up ssh keys appropriately and it's even easier to allow the specification of a remote directory by adding a parameter to grab()
More difficult is addressing the other negatives. It would be nice to pick a dynamic port but as far as I can tell there is no elegant way to pass that port to the shell on the remote host; As best as I can tell, OpenSSH doesn't allow you to set arbitrary environment variables on the remote host and bash can't take environment variables from a command line argument. Even if you could pick a dynamic port, there is no way to ensure it isn't used on the remote host without connecting first.
You can use SCP protocol for tranfering a file.you can refer this link
http://tekheez.biz/scp-protocol-in-unix/
The best way to use this you can expose your files over HTTP and download it from another server, you can achieve this using ZSSH Python library,
ZSSH - ZIP over SSH (Simple Python script to exchange files between servers).
Install it using PIP.
python3 -m pip install zssh
Run this command from your remote server.
python3 -m zssh -as --path /desktop/path_to_expose
It will give you an URL to execute from another server.
In the local system or another server where you need to download those files and extract.
python3 -m zssh -ad --path /desktop/path_to_download --zip http://example.com/temp_file.zip
For more about this library: https://pypi.org/project/zssh/
You should be able to set up public & private keys so that no auth is needed.
Which way you do it depends on security requirements, etc (be aware that there are linux/unix ssh worms which will look at keys to find other hosts they can attack).
I do this all the time from behind both linksys and dlink routers. I think you may need to change a couple of settings but it's not a big deal.
Use the -M switch.
"Places the ssh client into 'master' mode for connection shar-ing. Multiple -M options places ssh into ``master'' mode with confirmation required before slave connections are accepted. Refer to the description of ControlMaster in ssh_config(5) for details."
I don't quite see how that answers the OP's question - can you expand on this a bit, David?