Posts with the tag networking
Find out more about IP addresses (IPv4 and IPv6) using the Python module IPy:
#!/usr/bin/env python from IPy import IP ip_s = raw_input('Please enter an IP address or range: ') try: i =...
This is a really compact and cheap router to take with you to hotels etc. to secure your internet access via VPN or redistribute a network.
I put some photos I made of...
The RFC 2217 standardizes the transmission of serial connection data via Ethernet, allowing to change remote serial port parameters (such as speed, parity, stop bits) over TCP using NVT (Network Virtual Terminal).
Connection between your serial device and the Ethernet
- YPort - a hardware and software solution (microcontroller AVR ATmega based...
cd ~/Downloads curl -C - -O http://synergy.googlecode.com/files/synergy-1.4.5-MacOSX107-x86_64.dmg open synergy-1.4.5-MacOSX107-x86_64.dmg cd /Volumes/Synergy/ cp -r Synergy.app /Applications/
Start the server:
synergys -f --config ~/synergy.conf
# sample synergy configuration file # # comments begin with the # character and continue to the end of line. # comments may appear anywhere the syntax...
Go to System → Preferences → Keyboard Shortcuts and set the shortcut for
Hide all normal windows and set focus to desktop to something sane like
Alt + D
update 2011-07-13: This happened again when I used Ubuntu 11.04 inside a NX session on a Mac OS X host computer. :(
Installation on Ubuntu:
sudo aptitude install ipwatchd-gnotify
if configured correctly (true by default) it will show you graphical warnings for IP conflicts as well as create log entries in
/var/log/syslog (check for log messages containing
Advanced configuration options are described and have to be set in the file
/etc/ipwatchd.conf. This could...
You can use tcpdump to debug TCP/IP connections.
How it works
1st console run tcpdump:
philipp@lion:~$ sudo tcpdump -i lo tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on lo, link-type EN10MB (Ethernet), capture size 96 bytes 09:55:05.968006 IP lion > lion: ICMP echo request, id 5745, seq 1,...
When someone has taken your IP, react!
Set your IP to the correct one (belonging to you):
sudo ifconfig eth0 18.104.22.168 netmask 255.255.255.0
and run arping to get the IP back on your side:
sudo arping -U -c 3 -I eth0 22.214.171.124 sudo arping -A -c 3 -I eth0 126.96.36.199
Warning: my experience with gmailfs was not excellent! It was a bit slow and you always risk to lose data you stored on that account.
based on IMAP: http://sr71.net/projects/gmailfs/
(it used to be http://richard.jones.name/google-hacks/gmail-filesystem/gmail-filesystem.html but this was based on the Webinterface and that changed often)
gmailfs works with FUSE....
An easier solution just by setting a line in the configuration of the ssd daemon can be found in the blog post Chroot SFTP users.
sudo aptitude install scponly
sudo -s cd /usr/share/doc/scponly/setup_chroot gunzip setup_chroot.sh.gz chmod +x setup_chroot.sh ./setup_chroot.sh
this adds the user etc...
Filter the authentication log file for failed authentications and count the attempts (lines in the log file):
grep -i fail /var/log/auth.log | wc -l
Check for all attacks with non existing usernames:
grep -i "Failed password for invalid user" /var/log/auth.log | cut -d " "...
When you don't want other software (like network manager) to mess with your DNS server settings, make
sudo chattr +i /etc/resolv.conf
It can be undone like this:
sudo chattr -i /etc/resolv.conf
If wireshark reports many wrong checksums, this can be caused by checksum calculations done by hardware which means that the wrong checksums reported by Wireshark are simply meaningless.
If you're sure, that's the problem, you may simple not care about wrong checksums:
- Turn off the checksum offloading in the network...
gpg --keyserver subkeys.pgp.net --recv-keys 0x94C09C7F gpg --export 0x94C09C7F | sudo apt-key add - echo "deb http://mirror.noreply.org/pub/tor jaunty main" | sudo tee -a /etc/apt/sources.list sudo apt-get update sudo apt-get install tor
setup of a HTTP-Proxy for tor Tor being a Socks-Proxy (not a HTTP-Proxy) means you can't...
screen you can run an SSH command without interrupting the execution when the connection is lost. In case of a connection loss, all you have to do is to reconnected to the SSH host again when a connection is available and attach to the former
screen session again.
Use the CLI programs host or dig to resolve domain names to IPs (and get some more information).
So when you run
host example.com for example you will get the answer
example.com has address 188.8.131.52 example.com has IPv6 address 2620:0:2d0:200::10
The output of the run of
dig example.com is more detailed:
If your ssh connection is established only with a delay of about 2-4 seconds (even when you are connected to a fast network), you can try the tips in this post.
What to try first
Debug you ssh connection: using
ssh firstname.lastname@example.org -p 28 -vvv (note the -vvv switch at the end).
tinc is a Virtual Private Network (VPN) daemon that uses tunnelling and encryption to create a secure private network between hosts on the Internet. It runs on many platforms including Linux, FreeBSD, OpenBSD, NetBSD, MacOS/X, Solaris, Windows 2000, XP, Vista and Windows 7.
The installation of tinc on Ubuntu Linux is...
run netstat like this:
sudo netstat -lntup
and you get an output like this:
Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State ...
sudo gedit /etc/apt/sources.list
Then add to the file:
# Google Chrome deb http://ppa.launchpad.net/chromium-daily/ppa/ubuntu intrepid main deb-src http://ppa.launchpad.net/chromium-daily/ppa/ubuntu intrepid main
And add the sign-key to you keyring:
sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 0xfbef0d696de1c72ba5a835fe5a9bf3bb4e5e17b5
Then update and install:
I don't like to set up an SMTP server without authentification but I needed it for a special hardware, the Koukaam NETIO 230A. It sends reports of its operation via unauthenticated SMTP emails.
sudo aptitude install postfix
With the very small tool
x2x you can move your mouse to the left edge of your local screen and will continue to move over to the remote desplay. Your keyboard works on both computers as well, and you can even copy-paste between the two computers. It looks like the...
Set Up Public/Private Key Authentication for SSH to Connect from Laptop ↔ Desktop Without a Password Prompt
On both Linux/Unix computers you have to make sure they have a public key
~/.ssh/id_rsa.pub. If it is not there yet, run:
ssh-keygen -t rsa -b 4096
The desktop should be able to connect to the laptop with no password: (we work on the desktop here):
scp ~/.ssh/id_rsa.pub philipp@laptop:~/tmp-key.pub ssh philipp@laptop cat...
On Windows Systems you can send short messages using the
net send command. This is also possible using
smbclient on Linux:
smbclient -M Hostname_or_IP "nachricht"
You can also pipe-in the text to send:
echo "Nachrichtentext" | smbclient -M Hostname_or_IP
Or directly send textfiles up to 1.6 KB:
sudo apt-get install lighttpd
The webdocuments root folder is
Refer to the ubuntugeek.com site for more features (php etc) .
change ownership of /var/www in order to be able to put files there as normal user
sudo chown philipp /var/www sudo chgrp philipp...
OpenSSH supports jailing SFTP users to a directory (using
chroot) just by changing its configuration file:
Basically you add the users you want to jail to a linux user group (
sftp) and add the following lines to
### Comment out the following line: #Subsystem sftp /usr/lib/openssh/sftp-server ### and replace with: Subsystem sftp...