In this tutorial I will try to explain the different ways to set up frame-relay topologies in conjunction with OSPF. The topology I will use for this is the same one as I used before in the NTP and URPF posts.
For the most basic topology where R1 is the HUB and R2 en R3 are [...]
NTP synchronizes timekeeping among a set of distributed time servers and clients. This synchronization allows events to be correlated when system logs are created and other time-specific events occur.
See below an example of an NTP configuration
Time based ACL Example :
Ever needed to create a time-based ACL?
The following example denies HTTP traffic on Monday through Friday between the hours of 8:00 am and 6:00 pm:
The Unicast RPF feature helps mitigate problems caused by the introduction of malformed or forged (spoofed) IP source addresses into a network by discarding IP packets that lack a verifiable IP source address
So in other words, when you enable ip verify unicast on an interface what it basically does is check if the source address [...]
RMON Example :
-Configure RMON to track the five minute CPU average (lsystem.58.0)
-If the utilization is over 85% generate the event “CPU Above 85%”
-If the utilization is below 30% generate the event “CPU Below 30%”
-Sample the MIB every 60 seconds
-Trap the events to the SNMP NMS at 1.2.3.4 using the community string CISCO[...]
I stumbled upon this website with lots of CCIE SP mini-scenario’s, check it out here
Etherchannel protocols
When it comes to making etherchannels on cisco-switches there are three flavors you can choose from when it comes to using negotiation protocols:
LACP
- mode active
- mode passive
PAGP
- mode desirable
- mode auto
None
- mode on
No negotiation protocols (only choice is on):
Here some examples of advertising your loopback interfaces into OSPF
1. OSPF loopback advertisement:
Advertise the loopback0 network into area 17.
These networks should appear in all other OSPF enabled routers with a /24 subnet mask.
interface loopback 0
ip ospf network point-to-point
!
router ospf 1
network 150.1.1.1 0.0.0.0 area 17
BGP attributes I use most :
Weight
- traffic going out
- Default = 0 Higher is preferred
- Paths that the router originates have a weight of 32768 by default
Local preference
- traffic going out
- Default = 100, Higher is preferred
Med
- traffic coming in
- Default = 0 lower is preferred
- A lower MED value is preferred over a higher
Regular expressions
Character Description
^ Matches the beginning of input
$ Matches the end of input
| A logical “or” statement
. Matches a single character
Ever wanted to put a question mark in the enable password on a cisco router?
You can do this by following this procedure :
–Enter abc.
–Type Crtl-v.
–Enter ?123.
The password is now abc?123, when issueing the password you don’t have to type in the Ctrl-v.
Decrypting password 7 passwords can be done on Cisco routers, so you actually don’t have to go onto the internet and download a password-decrypter. Here is how you do it:
Rack1R1(config)#key chain MYKEY
Rack1R1(config)#key 1
Rack1R1(config)#key-string 7 puthereyourpasswordyouwanttodecrypt
Rack1R1(config)# show key chain
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