Snake test is usually performed to check whether a device can handle traffic Tx/Rx to/from all active interfaces at line-rate. The snake test is usually performed as below;
Traffic SENDER—- 0/1(Router)0/2 —- 0/3(same router)0/4—-0/5(same router)0/6— Traffic RECEIVER
ports 0/1-2 are untagged(access ports) in a vlan; say vlan2
ports 0/3-4 are untagged(access ports) in a vlan; say vlan3
ports 0/5-6 are untagged(access ports) in a vlan; say vlan4
So, packets sent by the SENDER at line-rate will be received at the RECEIVER. Same can be done vice-versa. ie: line-rate traffic from RECEIVE to SENDER. Continue reading
When a router receives a packet, it would check the routing table to forward the packet to the egress(outgoing) interface based on the destination IP address. If we need to forward packet based on other field, like source IP etc, we need to use PBR rules to override the routing table entry. The issue is, after configuration PBR, the packets are not routed to the firewall as in the PBR rule rather forwarded based on the routing table.
- PBR was configured to route packets to a firewall instead of taking the normal route as in Routing table. Continue reading
VNC is used to display X windows session running on a remote server. For network engineers, it is really useful to have Konsole/xterm session running on a Linux server connecting to network devices. Whenever we need access to the switches/routers, we can just login to VNC server using a VNC client. All sessions will be active (unless idle timeout is configured on switches/routers) and ready to use.
Steps to install VNCserver in Linux: Continue reading
Objective: To generate a default-route in L1 database by an L1-only IS.
Commands/configurations are from FTOS. Hope, the ISIS behavior will be same across all network vendors.
- The default behaviour in ISIS: If an L1L2 IS has L2 adjacency with another IS in *different* area, then L1L2 IS will send L1 LSP with attached bit set to all its L1 neighbors. Continue reading
RIP: Routing Information Protocol in IOS
- Distance vector protocol. Routing by rumour.
- Make sure “ip routing” is enabled. Continue reading
Posted in IOS
Tagged ios, rip
If a Cisco router fails to load an IOS because of less flash size/register flag/any other reason, it will stuck in the ROMMON mode.
1. To recover, You should have the IOS image in the flash/external disks. Continue reading