Nmap port-unreachable for busybox binaries - udp

I need to scan the open ports from ubuntu pc to nxp based board. I used nmap for that purpose. In Board busybox provided micro clients like ntp & udhcpc. Actually NTP is working as expected for syncing with the server time. But while scanning from ubuntu pc it shows port-unreachable.
So I tried installing NTP from yocto image and removed ntp from busybox. Now nmap shows the port is open.
Is there any way to proceed further while using busybox clients? Since dhcpclient & NTP produced from yocto makes the size of the filesystem larger.

Related

Remote access to a Jetson Nano

I am trying to remotely access a Jetson Nano from my mac. So far I have done the following:
I installed microsoft Remote Desktop on my mac
I connected the nano with my mac through the Micro-usb Port
In network I could see the connection "linux for Tegra" where my nano would be 192.168.55.1
With this I still cannot remote access the nano
So I open a terminal and typed
>ssh username#192.168.55.1
and I could access the nano terminal.
So I think now, I have to do
>sudo apt install xrdp
in order to be able to remotely access the GUI.
However, the nano does not have internet connection.
Is there a way that it can use the internet connection of my mac to do this?
(I am reading a tutorial on Rasppi with windows and apparently this is possible)
One of the approaches is to install X server for mac and then use ssh -Y username#192.168.55.1. You will get the command line shell first but you can type in commands like gedit - they windows will show up on the host.
192.168.55.1 is the same network as any other. All tools supposed to work over TCP/IP should work with it as well.
USB is a Serial connection by default.
On windows use a putty based tool.
For example start with MobaXterm > New session > Serial #11500
Login
Password
It won't forward internet by default.
Best simple way is to plug in your phone as USB network sharing and plug in to the laptop via micro-USB.
For Linux, Ubuntu, use a serial ("COM" related stuff) tool.
If you want to do ssh through USB it will require custom editing of networking file.
By default Nano is using a bridge called L4TBRO on 192.168.55.1, laptop is client in .100.
DNS server is on Nano's side.
You would have to create a new interface but using your laptop as DCHP and DNS servers.
Note that usb can power the Jetson Nano for continuous execution on a recent laptop. Some recommends not to and it may crash if you run a compilation on all cores. (if it crashes, just disable 2 cores via nvpmodel -m 1)

Change VNC boot configuration in Raspbian Jessie

When I boot my Pi 3 connected to a monitor, the built-in VNC server loads with the monitor's resolution. When I boot the Pi 3 without a monitor connected, it defaults to a much lower resolution.
I've found this lower resolution extremely difficult to code on as I can't see very much of my code at once.
Is there any way to set a configuration file and specify the resolution the VNC server launches at?
Found after more digging:
The boot configuration in Raspbian (I'm using Jessie) needed to be modified.
To do this I ran sudo nano /boot/config.txt in terminal to open the file as superuser in nano.
I changed (un-commented) the following lines:
hdmi_force_hotplug=1
hdmi_group=1
hdmi_mode=16
mode=16 is standard 1080p IIRC
Modes can be found here: Raspberry Pi Configuration
From what I understand, what we're doing is forcing the Pi to boot as if a monitor were connected, then specifying the resolution.

Configuring SSH over USB on ARM AM335x running angstrom linux 3.2.0

I have a AM335X ARM processor on a custom board. I am running angstrom linux 3.2.0 on it.
My build environment is a 64 bit laptop running Ubuntu 12.0.4.
I was hoping (I am a newbie), someone could explain what I need to do to configure the board (and host desktop) to run SSH over USB.
Any help would be greatly appreciated
It depends whether you have OTG port or not. If yes, you should configure it to emulate a network device. Connect your board to your laptop and you should see a new networking device (usb0 or something like this). Configure IP addresses for both host usb0 and one on your board and you're done having an extra IP subnet, where you can ping, SSH etc.

Simple OS X TCP forwarding server/service

As part of a TDD (test driven development) project I want a simple OSX service/server that simply forwards data between two clients. The purpose is to enable communication between one piece of code running in iOS (being tested) and another running in OS X.
I think I need both parties to connect to the server for the duration of the test, which points at TCP
There are lots of examples for creating simple clients using NSStream, but have failed to find what creates the Server side.
I would have thought it would be normal for this forwarding software to be a client of the final server, rather than both the other pieces of code being a client to it (as it's both counter-intuitive and somewhat difficult to acheive):
iOS App -> Forwarding Server -> OSX Server
You can achieve this using netcat (which is installed by default on OSX), simply with:
$ nc -l -p local-port -c "nc osx-host osx-port"
(see below)
and the iOS app simply needs to connect to local-port on whatever machine this forwarding server is running on.
EDIT When I actually tested my answer I found that the netcat supplied with OSX cannot support port forwarding, and the answer I supplied only works with the Linux version (I believe there is a BSD-rewrite which OSX uses).
Anyway, this can be achieved if you are happy to install macports and use socat. Here's a working example that redirects port 8888 to www.google.com:80:
$ sudo port install socat
$ socat TCP-LISTEN:8888,fork TCP:www.google.com:80
If you then connect to http://localhost:8888 within your browser, this will hit Google.
Port Forwarding In Windows for iOS .
1. Install Python 2.7 on windows system
2. Connect your iPhone to windows system
3. Download USB MXD1.0 and put it in C Drive
4. Run Command Prompt : OpenC:\usbmuxd-1.0.8\python-client in cmd
5. Run **\Python27\python.exe tcprelay.py -t local port:remote Port**
Eg :**\Python27\python.exe tcprelay.py -t 9892:9892**

Smalltalk web app deployment on headless Linux server

We wrote a small prototype web app using Pharo and Seaside and we want to now demonstrate to the suits that the app can be deployed into our standard Linux build. We use a mix of CentOS, Ubuntu Server and Gentoo which are run headless since most of our apps are JAVA/Apache based. Only port 80 and 443 are open to the outside world.
What are your experiences when hosting Seaside/Smalltalk server side apps?
it runs great, btw you can get free hosting for your seaside app at:
http://www.seasidehosting.st/
for more power you'd need your own server of course...
some benchmarks here:
http://gemstonesoup.wordpress.com/2007/10/19/scaling-seaside-with-gemstones/
The Seaside Book has a chapter on deployment. It describes how I typically deploy a Seaside application.
I just use a ssh tunnel to get the X display on my local machine. I'm using slicehost (US) from the Netherlands, so I have a ping time of 135 ms. That's not that nice, but ok.
Next step will be Lukas Renggli's remote frame buffer package to use a vnc viewer.
Let's see what Miguel Cobá had to say about it on it on the Gemstone mailing list:
If you have already installed a RFB in your machine then use it.
If you have RFB installed in your image and it is accesible from your
client machine, use it
But, both of them are unencrypted. If you want to encrypted you must
setup a tunnel (maybe with ssh or maybe TLS).
I think that that is redundant because you must use a tunnel and then
the RFB. So what I do, in linux is to install the minimal X libraries
and then forward the X session to my local machine.
In the server (Debian/Ubuntu instructions):
aptitude update
aptitude install xbase-clients
aptitude install xtightvncviewer
Test it from the client machine:
ssh -X remote_server
squeakvm gemtools.image &
This will start the squeakvm process on the server, but all the graphics
will be shown on the local machine (the Xserver for this particular
scenario).
Also, if you install RFB on some of your images and start them headless,
you can use xtightvncviewer to connect to inside the image through the
RFB server.
ssh -X remote_server
xtightvncviewer localhost:0 &
this will run the xtightvncviewer on the remote server but, again, will
show on your local machine. Supposing you have your image in the remote
server running RFB in the first display.
Which is the advantage:
- You don't have to open ports for RFB on the remote server
- You transmit everything encrypted through ssh
- You only run the commands on demand in the remote server. You don't
have to have VNC running always.
- You can configure your RFB in the image to accept only localhost
connections and not from everywhere.
Martin McClure adviced me to take a look at NoMachines NX (less chatty X),
but that's still on my todo list.
For another set of deployment instructions, take a look at Miguels blog
The blogosphere's been talking about this issue recently.
Doug Putnam wrote up his experiences in installing Seaside (on Pharo) on his Slicehost slice, working off James Robertson's writeup (which uses VisualWorks, I suppose?).