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 »
Here is a quick how to force your network interface speed and duplex on RHEL/CentOS Linux. Make sure you have the network tools installed : yum install ethtool net-tools To apply the configuration without having to restart the network service or reboot your system, simply do this command with your settings : ethtool -s <INTERFACE>… Read More »
Getting this error doing a commit after assigning a subnet to a L3-interface vlan on your Juniper device? user@EX4200# set interfaces vlan unit 100 family inet address 1.1.1.1/8 user@EX4200# commit synchronize comment “add subnet to vlan 100” [edit protocols] ‘bgp’ [edit protocols] ‘ospf3’ [edit interfaces vlan unit 100 family inet] ‘address 1.1.1.1/8’ Cannot have the… Read More »
Have you seen this in the logs of one of your iBGP router? rpd[0000]: bgp_recv: peer 0.0.0.2 (Internal AS 00000): received unexpected EOF You can also notice this related error on your eBGP router : rpd[0000]: bgp_listen_accept: Connection attempt from unconfigured neighbor: 0.0.0.2+00000 This mean you have a inexistant or unconfigured community for this neighbor trying… Read More »
Ending up with this error while trying to join a workstation to Active Directory domain? Computer Name/Domain Changes The following error occured attempting to join the domain “domain.local”: The network path was not found. The possible cause is one of the required services for Active Directory client computer is not started. Make sure those two… Read More »
Getting this error trying to add a layer 3 routing interface (l3-interface) to a VLan on JunOS? root@EX4200# set vlans v1000 l3-interface vlan.1000 root@EX4200# commit comment “add l3-iface to vlan 1000” [edit vlans v1000 l3-interface] ‘l3-interface vlan.1000’ Interface must already be defined under [edit interfaces] error: commit failed: (statements constraint check failed) [edit] root@EX4200# … Read More »
Getting this error message while trying to bring up your newly configured bridge interface on RHEL/CentOS Linux? You are missing “bridge-utils” package. Simply install it as followed and bring up the interface again : yum install bridge-utils NOTE : Click here to see our HowTO create a bridge interface article
To find out the network ports currently opened by running software on a Linux machine, simply use LSOF (list open files). This can also sort out the communication port as well. To display IPv4 ports : lsof -Pnl +M -i4 To display IPv6 ports : lsof -Pnl +M -i6
Adding a bunch of IP to windows through the GUI is a nightmare! Fortunately, you can enter a single command that will add them in a second. Simply open the command prompt and type the following command : FOR /L %I IN (<IP_START>,1,<IP_END>) DO netsh interface ip add address “Local Area Connection” <IP_SUBNET>.%I <IP_NETMASK> Let’s… Read More »
The easiest way of disabling ICMP echo request on Linux is doing it on the kernel level. To disable ICMP immediately on a running system, simply enter the following command : echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all This command will not survive to the next reboot. To make it permanent, edit : vi /etc/sysctl.conf And add :… Read More »