I am running Mininet as VM and my host machine is Windows 10. I have been successfully able to setup X1 forwarding. The ssh client i am using to login into Mininet VM from host is Mobaxterm.
When i start the mininet topology using sudo mn, then xterm h1 open a display window. All fine.
But the same is not working when I launch mininet custom topology by running python programs.
mininet#mininet-vm:~/SocketProgrammingMininet/mininetTopologies$ sudo python vlan_ex1.py
mininet> nodes
available nodes are:
h1 h2 h3 h4 r s5
mininet> xterm h1 << No h1 host's display.
mininet#mininet-vm:~/SocketProgrammingMininet/mininetTopologies$ sudo mn
mininet> nodes
available nodes are:
c0 h1 h2 s1
mininet> xterm h1 << Window for H1 host opens up.
Where is the problem here ? Do I need to do some settings in python program or the way i run it ?
I ran a script-generated topology in the same setup (Win10 + mininet VM + scripted topology) and I can confirm that no xterm opens up for me either. I made sure my console was correctly using X-server (wireshark opens beautifully).
Running a script that includes a call like os.system("xterm") from each host made it clear as to what the reason may be: my message was my error was MoTTy X11 proxy: Unsupported authorisation protocol. I also see a xterm: Xt error: Can't open display %s which makes me think it can be an xauth thing.
When you look into the documentation of Mininet, though, there's a section about debugging through the use of xterm displays, quoting:
To start an xterm for every host and switch, pass the -x option:
$ sudo mn -x
After a second, the xterms will pop up, with automatically set window
names.
Alternately, you can bring up additional xterms
This helped me and it should solve your problem... if you still have it after all this time ;)
Related
I have a VM instance on Oracle Cloud (Ubuntu 22.04) set up with ZeroTier to act as a web server for some services that should work with my local Synology NAS.
For some of those services I also need to mount three SMB shares from my NAS with the ZeroTier tunnel, but I can't make it work.
I used mount and mount.cifs plenty of times with automounting too, this time it acts very strange:
running the mount command seems to succeed from the console, but /var/log/syslog reads
CIFS: VFS: \\XXX.XXX.XXX.XXX has not responded in 180 seconds.
Reconnecting...
if trying to access one of the shares (ls or lsof or cd or any other command), it succeeds for only one of the shares (always the same one), but only for the first time any command is given:
$ ls /temp
folder1 folder2 folder3
any other following command just "hangs" as if they system is working on something, but it stays like that indefinitely most of the times:
$ ls /temp
█
Just a few times it spits out this error
lsof: WARNING: can't stat() cifs file system /temp
Output information may be incomplete.
ls 1475 ubuntu 3r DIR 0,44 0 123207681 /temp
findmnt reads:
└─/temp //XXX.XXX.XXX.XXX/Downloads cifs rw,relatime,vers=2.0,cache=strict, username=[redacted],uid=1005,noforceuid,gid=0,noforcegid,addr=XXX.XXX.XXX.XXX,file_mode=0755,dir_mode=0755,soft,nounix,serverino,mapposix,rsize=65536,wsize=65536,bsize=1048576,echo_interval=60,actimeo=1
for the remaining two "mounted" shares, none of them seems to respond to any command, not even the very first command, and they just hang like the one share that, at least, lets me browse for one time;
umount and umount -l take at least 2-3 minutes to successfully unmount the shares.
Same behavior when using smbclient and also with NFS shares from the same NAS.
What I have already tried:
update kernel and all packages;
remove, purge and reinstall cifs-utils, smbclient and so on...
tried mounting the same shares in another client / node within the ZeroTier network and it works just fine; also browsing from Windows and Android file manager apps with and without ZeroTier works flawlessly;
tried all SMB versions including SMBv3 and SMBv1 (CIFS);
tried different browsing or mounting methods / commands including mount, mount.cifs, autofs, smbclient;
tried to debug what happens behind the console, but didn't found anything that seems related to this in logs, htop or anything else. During the "hanging" sessions there is no spike in CPU, RAM or Network usage in either the Oracle VM or Synology NAS;
checked, reset and reconfigured all permissions on my NAS for shares, folders and files recursively and reconfigured users groups permissions.
What I haven't tried yet (I'll try as soon as possible):
reproduce this on another Oracle VM configured the same as the faulty one and another with a different base image (maybe Oracle Linux?);
It seems to me that the mount.cifs process doesn't really succeeds in mounting the share correctly, as it doesn't show as such anywhere. It also seems an issue not related to folder/file permissions, but rather something related to networking?
A note on something that may or may not be related to this: ZeroTier on my Synology NAS does not seems to work with IPv4 only - it remains OFFLINE. The node goes ONLINE only when IPv6 is enabled, but I must say that this is the only node in my ZT network that shows a IPv6 as public IP in the ZT web GUI - the other nodes show IPv4 public addresses.
If anyone has any clue on this, I'll be happy to support and reproduce any advice. Thank you!
I'm using YailScale, but I presume it will work the same.
You need to add the port 445 to /etc/iptables/rules.v4 just under the SSH setup like below:
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 445 -j ACCEPT (like this)
Then you need to edit the interfaces in /etc/samba/smb.conf to:
interfaces = lo tailscale0 100.0.0.0/24
Obviously, my interface is tailscale0, but yours will be different. Use ip link show to find yours. You may also need to change your IP range to suit ZeroTeirs, such as 100.0.0.0/24, which is what tailscale uses.
Then reboot!
I couldn't get it working without doing this.
I successfully implemented this, which blocks all internet connections on my Linux machine UNLESS it connects via a specific VPN :
https://www.comparitech.com/blog/vpn-privacy/how-to-make-a-vpn-kill-switch-in-linux-with-ufw/
If I manually execute openvpn3 session-start --config ~/Desktop/config.ovpn, it successfully connects via the VPN.
I used to have this command in a script (that has #!/bin/bash as header) which ran at device bootup without any issues, UNTIL I configured ufw for the killswitch above (now ufw runs on device bootup).
I use openvpn3 so using instructions in the above tutorial for openvpn commands didn't work at all.
I even tried using a sleep in my bash script to get it to wait a while until after bootup. Doesn't work. But if I issue the connection command manually in the command prompt, it works.
Please help! I need it to connect automatically. Much appreciated!
After spending a whole day on this, I figured out a solution. I found an article that guided me : https://www.howtogeek.com/687970/how-to-run-a-linux-program-at-startup-with-systemd/
I set up a service item using systemd (systemctl) just for that command to connect. Here is what my entry looks like :
#/etc/systemd/system/connectvpn.service
[Unit]
Description=Connect VPN
After=ufw.service network.target
Requires=ufw.service
[Service]
Type=oneshot
ExecStart=/usr/local/bin/connect
#/usr/local/bin/connect
#!/bin/bash
openvpn3 session-start --config /home/xyz/Desktop/config.ovpn
Working nicely now, connects to the VPN on bootup.
I need to know how to connect to a beaglebone (or beagleboard) with SSH when I plug it into a new network with an ethernet cable like this:
$ ssh root#beaglebone.local
So far I've only been able to access it like this, if I know the IP address:
$ ssh root#<ip_address>
But I don't always know the IP address of the board on new networks so I'm hoping to access it with with a name like: beaglebone.local.
Right now when I try to do this I get this error:
"ssh: Could not resolve hostname beaglebone.local: nodename nor servname provided, or not known"
I checked the hostname and hosts files, and added "127.0.0.1 beaglebone" to the hosts on the beaglebone, but not sure what else I can do?
# cat /etc/hostname
beaglebone
# cat /etc/hosts
127.0.0.1 localhost.localdomain localhost
127.0.0.1 beaglebone
I had a similar issue running my beaglebone on Angstrom-Cloud9-IDE-GNOME-eglibc-ipk-v2012.05-beaglebone-2012.04.22.img.xz. In this distribution, "beaglebone.local" should appear on the network after the system boots.
About 50% of the time after reboot, "beaglebone.local" would not appear on the network (although the bone would be available by IP address). When this happened, "systemctl status avahi-daemon.service" showed that the avahi-daemon failed with "exit code 255". Interestingly, a subsequent "systemctl start avaihi-daemon.service" would always be successful and "beaglebone.local" would appear on the network.
Also "journalctl | grep avahi" returned a single message stating something like "Daemon already runnin gon PID NNN".
So, I "fixed" the problem by adding the line "ExecStartPre=/bin/rm -f /var/run/avahi-daemon/pid" to the [Service] section of /lib/systemd/system/avahi-daemon.service. With this addition, "beaglebone.local" now appears on the network 100% of reboots.
I say "fixed" (i.e., in quotes) because I have not been able to track down the root cause that is leaving around the stray avahi pid file(s) and thus don't have a true fix.
-- Frank
For 'beaglebone.local' to work, your host machine must recognize Zeroconf. The BeagleBone uses Avahi to tell other systems on the LAN that it is there and serving up applications and that it should be called a 'beaglebone'. If there are more than one, the second one is generally called 'beaglebone-2.local'.
I hate answering my own questions. The following hack will work until a better way emerges:
This shell script (where xxx.xxx.xxx is the first three numbers in your computer's IP) will find your beaglebone or beagleboard (that is plugged-into ethernet on a new network with DHCP) by looping through all the ip address on the subnet and attempting to login to each as root. If it finds one then try your password. If it doesn't work just hit enter until the loop starts again. If it doesn't find the board then something else is probably wrong.
for ip in $(seq 1 254); do ssh root#xxx.xxx.xxx.$ip -o ConnectTimeout=5; [ $? -eq 0 ] && echo "xxx.xxx.xxx.$ip UP" || : ; done
UPDATE 1
Today I plugged-in the beaglebone and saw Bonjour recognize that it joined the network. So I tried it and it worked. No idea why it decided to all of the sudden but it did. Strange, but true.
I had this issue quite often with Mac OS X 10.7. But unlike Frank Halasz "systemctl status avahi-daemon.service" shown no failure. And in fact the problem was on the Mac side. Restarting Bonjour with the following commands fixed the issue.
$ sudo launchctl unload /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
$ sudo launchctl load -F /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
If you issue a scp command between 2 remote servers, will the traffic flow directly between the hosts, or will it flow from Remote1 => Local Machine => Remote2?
For example I issue this command on my laptop:
scp user1#remote1.com:/Files user2#remote2.com:/Files
Newer versions of scp (since 2011) have the option -3 which will route the traffic through your local machine. This is useful if the hosts are on different networks and can't see each other. Found this on SuperUser. From your linked article it seems like normally the hosts will try to connect directly to each other.
Looks like it can be done.
If your linux/bsd/unix or Mac do not have the -3 option, just compile the last version from: http://www.openssh.org/portable.html
It is as simple as:
./configure; make ; sudo make install
It will be installed on /usr/local/bin by default. I just did that on my Mac OS X Lion.
I connect to a solaris (10) server through SSH from my linux machine.
However, when I attempt to open another terminal using " xterm" , then it does not work.
I set the DISPLAY env variable to 127.0.0.1:0.0, but it gives the following error:xterm Xt
error: Can't open display: 127.0.0.1:0.0
Please suggest a solution to rectify this.
Thanks
-Mike
That's the address of the X server on the target machine. You need to address the X server on the client machine on which you're working. The easiest way is to just use ssh -X or -Y, (see man ssh(1)) as
client: ssh -Y solaris
in order to connect to the remote machine; you need login info too
This just sets up an X connection, tunneled through ssh.
Otherwise, you can do it by hand as
client:
$ echo $DISPLAY
client:3:4
remember it's not *always* 0.0
$ xhost +solaris
You have to allow connections from the remote machine
$ ssh solaris
sets up a remote shell, you still need ssh login info
solaris:
$ export DISPLAY client:3.4
make sure its the server on 'client' you're using
$ xterm
This should now give you a 'solaris' xterm window on 'client'
As Charlie mentioned, use ssh -X hostname when connecting.
If all else fails enter xhost + on your remote machine. Hope that helps.
Set the display to your linux IP address, not localhost.
127.0.0.1 is localhost : therefore on the Solaris server, it's the server itself.