JunOS : Configuring the QSFP+ uplink ports on EX4300

By default, all QSFP+ ports on the EX4300 chassis are configured as virtual chassis ports (vcp). VC minimal (recommended) requirement is two ports, meaning that two out of the four ports can be used as regular 40 Gbps interfaces and/or for uplink purpose. Let’s assume we want to use the port #0 and 1 as… Read More »

MacOS : Unable to negotiate with 0.0.0.0 port 22: no matching cipher found

Having the following issue connecting to a device using SSH after upgrading to macOS High Sierra 10.13.2? Unable to negotiate with 0.0.0.0 port 22: no matching cipher found. Their offer: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se This is an expected behavior if you attempt to connect to a legacy system or network device running older version of SSH. To workaround… Read More »

Linux : How to show connected client of NFS export on the server?

Here is how to quickly show the connected clients to a NFS server. It might be useful to know before rebooting the server! On the server, execute the following command (replace <> with the NFS server IP address) : netstat -an | grep <NFS.Server.IP>:2049 Example : netstat -an | grep 192.168.45.32:2049 You should see a… Read More »

Windows : How to pause Windows 10 updates download

Since Windows 10, Microsoft made it harder for users to disable automatic updates and downloads. When triggered automatically, there is no function on the user interface to stop them, unfortunately. If you are running with the default settings, you might at some point end up working on your computer and noticed that your bandwidth was… Read More »

Linux : How to change User and Group ID

There might be some (rare) circumstances where you would like to change a UID or GID on Linux system. If you know what you are doing and the implication behind this change (see warning comment below), this can be achieved using the commands below. Change User ID (UID) : usermod -u <ID> username Example :… Read More »

ScreenOS : SSL error accessing the WebUI

If you are using the WebUI to manage your Juniper SSG / ScreenOS device, you probably encountered the following error accessing the page lately : ERR_SSL_VERSION_OR_CIPHER_MISMATCH If you use a browser that allow SSLv3, you will be able to access the device. However as we all know the weakness of this protocol, it isn’t ideal… Read More »

Linux : How to add rc.local in Debian 9

On Debian 9, the traditional “rc.local” has been deprecated. For traditional Linux users and administrators, there is a way to get it back using SystemD. See the procedure below : 1. Edit the non-existing file “rc-local.service” : vi /etc/systemd/system/rc-local.service 1.1. Add the following content to “/etc/systemd/system/rc-local.service” : [Unit] Description=/etc/rc.local ConditionPathExists=/etc/rc.local [Service] Type=forking ExecStart=/etc/rc.local start TimeoutSec=0… Read More »

Windows : Google Chrome freeze shortly after opening

I have encountered the following issue/symptoms with Google Chrome (version 56.0.2924.87) on Windows 10 : – Google Chrome crash shortly after opening, the application become unresponsive even while going to settings – Single tab opened with the default Google page – No 3rd party extension, only Google defaults After digging around, I found that the… Read More »

Category: PC

Linux : R1Soft failed backup of LVM configuration

Having the following error while executing a R1Soft backup on a Linux server? Failed backup of LVM configuration Failed to execute command ‘lvm.static pvs -o pv_fmt,pv_uuid,dev_size,pv_name,pv_mda_free,pv_mda_size,pv_all,seg_all,pvseg_all,vg_all,lv_all –nameprefixes –noheadings –units b –nosuffix –unquoted’ This seem to be related to the latest version. Apparently Idera are aware of the issue and working on a permanent fix. In… Read More »