Category Archives: Networking

JunOS : bgp_recv: peer (Internal AS 00000): received unexpected EOF

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 »

JunOS : Interface must already be defined commit error

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 »

Windows : Add entire subnet in a batch

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 »

Linux : How to disable ICMP echo request

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 »

OpenVPN : service failed to start due to unresolved dependencies: set([‘bridge’])

If you setup OpenVPN to be in bridge (layer2) mode instead using NAT/routing (layer3) and then restart the server to make the change effective, you probably noticed the following error message on the Status Overview page repeatedly : service failed to start due to unresolved dependencies: set([‘bridge’]) This is because there is no existing bridge… Read More »

Linux : How to create a bridge interface on RHEL/CentOS

A bridge interface is actually a virtual interface handled by a config file on your Linux system. Creating a bridge is quite simple, just follow those steps and you’re all set! 1. Create the bridge interface configuration file : vi /etc/sysconfig/network-scripts/ifcfg-br0 Add the the following parameters : DEVICE=br0 TYPE=Bridge BOOTPROTO=static ONBOOT=yes STP=on IPADDR= NETMASK= GATEWAY=… Read More »