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JunOS : Can’t have mastership priority configuration with preprovisioned set

Getting this error committing the changes on a pre-provisioned EX switches virtual chassis? root@EX4200# commit synchronize [edit protocols] ‘bgp’ [edit virtual-chassis] ‘member 0’ Can’t have mastership priority configuration with preprovisioned set error: configuration check-out failed {master:0}[edit] root@EX4200# This mean you tried to set a mastership priority on a pre-provisioned configuration and this is not allowed.… Read More »

JunOS : How to upgrade from USB stick

There are several ways to update your JunOS software but one of the common and safe method is doing through the CLI and a USB memory stick. First, get your software from Juniper.net first and save it to a MSDOS formatted USB stick. Then, follow those steps (as root, through serial console is highly recommended)… Read More »

Linux : Clocksource tsc unstable

Getting this output on your RHEL/CentOS virtual machine? Clocksource tsc unstable (delta = 000000000 ns). Enable clocksource failover by adding clocksource_failover kernel parameter. First find out the available clock sources : cat /sys/devices/system/clocksource/clocksource0/available_clocksource You will likely get the following results : kvm-clock tsc acpi_pm You are currently using “tsc” as per the initial output error, try… Read More »

VMware : Unable to connect USB device to VM with ESXi vSphere 5.5

I recently faced the following issue with VMware ESXi vSphere 5.5 hypervisor, trying to connect a USB device to a virtual machine. The host server was actually able to see the USB device : lsusb Bus 02 Device 04: ID 1058:0748 Western Digital Technologies, Inc. Bus 02 Device 03: ID 09eb:0131 IM Networks, Inc. Bus… Read More »

Dell PowerEdge : PERC 6i controller rejecting new drive for resync degraded array

I recently observed this strange behavior from a Dell PowerEdge 2950 with PERC 6/i RAID controller. – One drive member from a RAID-5 array was failed – I pulled out the defective drive and pop in a brand new drive – Strangely, it did not started to sync and after a few moment, the drive… Read More »

VMware : iSCSI LUN datastore no longer visible after outage

If after a power outage or ESX hypervisor shutdown your iSCSI datastores are missing, it might be caused by a lock on the LUN on your host machine. You may find this in your vmkernel logs : /var/log/vmkernel.log 2014-02-19T04:19:11.927Z cpu3:33477)NMP: nmp_ThrottleLogForDevice:2321: Cmd 0x88 (0x412e80814440, 0) to dev “t10.FreeBSD_iSCSI_Disk______74867ae04094000_________________” on path “vmhba37:C0:T1:L0” Failed: H:0x2 D:0x0 P:0x0 Possible… Read More »

JunOS : Setting up DHCP forwarding

Here is how to configure DHCP forwarding across VLans on JunOS Juniper devices. set forwarding-options helpers bootp server <DHCP_SERVER_IP> set forwarding-options helpers bootp interface vlan.<VLAN_ID> Example : Assuming your DHCP server IP is “192.168.1.1” and the VLans you want DHCP forwarding enabled are “1” and “2” : set forwarding-options helpers bootp server 192.168.1.1 set forwarding-options… Read More »

Dell : Default username and password for DRAC

Here is a quick reminder about the default username and password for Dell DRAC out-band server management : Username : root Password : calvin

Linux : How to generate UUID for network interface on RHEL/CentOS

UUIDs (Universal Unique Identifier) for network interface card can be generated using the following command : uuidgen <DEVICE> Example : uuidgen eth0 Then you can add it to your NIC config file (assuming your interface is eth0) : /etc/sysconfig/network-scripts/ifcfg-eth0 Add/modify the following : UUID=<uuid>

Linux : qmail-smtpd: qq soft reject (mail server temporarily rejected message (#4.3.0))

Did your Qmail server failed to receive a message including an attachment and showing this output in the SMTP logs? policy_check: remote sender@domain.tld -> local recipient@domain.tld (UNAUTHENTICATED SENDER) policy_check: policy allows transmission qmail-smtpd: qq soft reject (mail server temporarily rejected message (#4.3.0)): MAILFROM:<sender@domain.tld> RCPTTO:recipient@domain.tld tcpserver: end 0000 status 000 In this particular case, the version… Read More »