Working on our practical networking lessons our students and we, as their teachers, we usually configure several routers and switches (sometime up to ten), which are accessible remotely. For this we welcome the use of multi tabbed and especially multi exection clients.
It allows to efficentienly organize working space and run commands in one task on all connected network euqipments (for example to save running config).
This example shows how to generate 254 loop interfaces with assigned ipv4 addresses 172.16.0.1/24 up to 172.16.255.1/24. The code is:
enable
tclsh
for {set i 0} {$i < 256} {incr i} {
ios_config "int loop $i" "ip address 172.16.$i.1 255.255.255.0"
}
ios_config "end"
tclquitand you may just simply copy and paste it into a Cisco router CLI. Therefore first run tclsh within of privileged EXEC mode
Working with my HP Terminal server, which we are using as a remote console acccess solution allows us login into Cisco router console ports remotely, i'm loosing the Putty connection due to inactivity. However the PuTTY client can be configured to maintain a connection and not time it out. All what we need to do is setup built-in keepalive machanism:
Teaching CCNP ROUTE courses and describing the problematic of two-way routing redistribution I need an example describing the case which point out to the process of creating a routing loop. This example shows how such routing loop may arise using badly configured redistribution process andusing bad seed metric. The topology with two redisitributing routers creates routing feedback (two way, multipoint redistribution). The loop is created for packets routed from the ospf network to the 3.0.0.0/8 destination network.
Once if we are allowed download zipped version of ccna curriculum (for example as an netacad instructor) we should be able run them locally without web server need. However there is a problem to display these curriculums by default as it contain embeded flash animation. This problem persists in different browsers (firefox, chrome, epiphany) for example.
In our Cisco NetAcad classes we had utilized built in Windows telnet client (of course we have putty instead), which was available in each system till Windows XP by default. In windows 7 the telnet client is not available by default, but we simply may do it available in few simple following steps:
We investigate a special topology condition, where a switch is connected itself on ports Faa0/1 and Fa0/2, and one of the port has BPDUFilter feature applied (i.e. simulating STP is switched off). Both ports are in the same vlan (vlan 1 here). The question is: Is there a topology loop?
Initial state
http://www.cisco.com/en/US/docs/ios/12_4t/12_4t11/ht_rawip.html
Cisco switches provides SPAN and RSPAN feature which is suitable for monitoring and capturing packets flowing through switch ports or VLANs. But this feature is not provided on Cisco routers, therefore if you look for it there is not result.
There is some confusion and misunderstanding regarding VTP (VLAN Trunking Protocol)+DTP (Dynamic Trunking Protocol) and this article will hopefully make it all clear. Most of the confusion comes from the statement that VTP is always a security threat to your network. There are even some CCIE material which I find to be wrong on this topic so my advice here is to test everything by yourself.