HowTos

Error Connecting to IOS-XR in the LAB I've created a new lab for testing using EVE-NG. Everything was fine.  But when I tried to connect to Cisco IOS-XR from my Jumphost, I saw the message: stack@devstack$ ssh cisco@192.168.0.7                                 Unable to negotiate with 192.168.0.7 port 22: no matching host key type found. Their offer:                                                                                                       Hmm... Their offer is nothing ! Connected to console and checked logs from the other side: RP/0/0/CPU0:May 30 10:33:08.510 : exec[65722]: %SECURITY-LOGIN-6-AUTHEN_SUCCESS : Successfully authenticated user 'cisco' from 'console' on 'con0_0_CPU0'  RP/0/0/CPU0:May 30 10:33:59.970 : SSHD_[65831]: %SECURITY-SSHD-6-INFO_GENERAL : no matching kex found: client ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ssh-rs

Intro When you spend a lot of time googling or reading documentation  trying to find a solution for some unexpected task and, at the end, it's startworking, you says "WOW! Now then I will use it next time!" But after few months you get the same task and... start from scratch. So I started writing  Tips and Tricks for every Network OS (Juniper, Cisco , Huawei etc.) in my notes.  After few years I decided to start publish my own collection. Hope it will help me and may be someone else to solve a problem in the future. Some of them are from Day One collection, some from my  everyday tasks.  Enjoy.

Linux is an amazing OS because you can do a lot inside it. Here is a bunch of Tips & Tricks I have found. Find the current time in the timezone you want: $ TZ='America/Los_Angeles' date Tue Dec 11 04:07:18 PST 2018 $ TZ='Europe/London' date Tue Dec 11 12:08:49 GMT 2018 Note: All available timezones can be found at /usr/share/zoneinfo. I recommend to view it using timedatectl list-timezones command. $ timedatectl list-timezones | grep Europe Generate random password string using  date and md5sum or sha256sum $ date | sha256sum | base64 | head -c 8 ; echo Y2RhODhh $ date | md5sum | base64 | head -c 8 ; echo YWNjYzU4 Generate pseudo-random string using OpenSSL  $ openssl rand -hex 8 d0388693bd744e0e $ openssl rand -base64 32 | head -c 12  ; echo uvics5KjODkt Generate random password string using gpg utility $ gpg --gen-random --armor 1 12

If you try to install Ubuntu at HP notebook, you will meet with some drawbacks. HP by default support Microsoft OSes only. You will find that some common things are working not as you expected. For example, you will lose your fingerprint or your touch-pad will work with limitation. But I didn't expect that such a common thing like Microphone mute/unmute key not work under Ubuntu. But it is so! To toggle mute of default microphone under Ubuntu at HP EliteBook you need an  pulseaudio and some scripting. Make sure that you have  pacmd  (from  pulseaudio-utils  package) and  notify-send  (from  libnotify-bin ). Use this script: #!/bin/sh pacmd list - sources | awk '\ BEGIN {default_found=0;} /^[\t ]*\*/ {default_found=1;} /^[\t ]*name:/ { if (default_found) { name=$2; gsub("[<>]", "", name); } } /^[\t ]*muted:/ { if (default_found) { if ($2=="yes") { mute=0; icon="mi

IPv6 is enable in Ubuntu by default, but I have found that without experiece you can spend a lot of time to find information for IPv6 network configuration  and operation. How to change IP address permanently Make changes in  file /etc/network/interfaces iface ens4 inet static  address 192.168.0.254  netmask 255.255.255.0  gateway 192.168.0.1 iface ens4 inet6 static   address 2001:db8::254  netmask 64  gateway 2001:db8::1 Temporary IPv6 Address Assignment stack@devstack# ip address add 2001:db8::254/64 dev ens4   Temporary IPv6 Address Deletion stack@devstack#   ip address del 2001:db8::254/64 dev ens4 Verify IPv6 address configuration stack@devstack# ip address dev ens4 3: ens4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000     link/ether 00:50:00:00:04:01 brd ff:ff:ff:ff:ff:ff     inet 192.168.0.254/24 brd 192.168.0.255 scope global ens4        valid_lft forever preferred_lft forever     inet

Today I created VPN to my home network. I need an access to my local resources and lab at home server from Internet. Here is how to enable OpenVPN server at ASUS router and how to configure сlient side at Windows.    First of all enable OpenVPN at  ASUS router. Step 1. Open VPN Tab in Advanced Settings Menu Step 2. In VPN Server - select OpenVPN section and enable OpenVPN Server Step 3. In Basic OpenVPN configuration change VPN details from General to Advanced Settings Here is a very useful recommendation:  You can change the default settings of the OpenVPN server to provide a custom OPVN file for a specific   connection type.  To use your own key, click the yellow link to modify settings.  Refer to the  System Log  for any error messages related to OpenVPN.  Before configuring the advanced settings of the OpenVPN server, ensure that these advanced settings options   are compatible with the OpenVPN software in the client devices. After checking System