Basic Router Configurations on Cisco Router
Today I am going to talk about the basic configurations on Cisco routers where i can define the basic commands like setting console password, assign VTY password, configuring IP addresses on the interfaces, Configuring the router for SSH access, Configuring basic IPv6 configurations on the router, configuring trunk based inter-VLAN routing, configuring IPv6 configurations manually and at last configuring OSPFv6 with the use of IPv6.
This is a basic article for the starters who are going to configure the router from the scratch. Most of the basic configurations are for demo purposes and you can use your IP addresses as per requirements in your network. Lets start with the basic configurations on the router now.
Above is the basic network topology where we have 3 layer architecture with the Cisco ASA firewalls and the routers. We are going to configure WAN routers with the basic configurations
This is a basic article for the starters who are going to configure the router from the scratch. Most of the basic configurations are for demo purposes and you can use your IP addresses as per requirements in your network. Lets start with the basic configurations on the router now.
 |
| Fig 1.1- Basic Network Topology |
Configure the Basic router
Router> enable
Router# config terminal
Router# config terminal
Router(config)# hostname ttlbits_ttlbits_R1
ttlbits_R1(config)# no ip domain-lookup
ttlbits_R1(config)# security passwords min-length 10
ttlbits_R1(config)# enable secret cisco12345
Now let's configure the console password on the Cisco routers, below is the basic example showing the configurations of console on router.
Setting Continue reading
Why bitcoin is terrible
For every day that passes I like bitcoin less. It’s bad for the world.
I have ranted about this many times, and it’s time I consolidate these rants into a blog post.
We’ll see with time if this rant ages poorly or not.
Section 1: Practicalities
What bitcoin is trying to achieve in payments
These would be good things:
- Anonymity
- Peer to peer and remote payments
What bitcoin is actually good for
Bitcoin today is pretty much only good for two things:
- Committing crimes
- Speculating on currency
If you’re not doing one of those, then don’t use Bitcoin.
If you are an online store then sure, accept Bitcoin. There’s moral problems with supporting Bitcoin (see rest of post), but as long as you immediately convert to fiat currency when you receive payment it’s fine for you. There are even companies out there that’ll guarantee an exchange rate so that you never have to get into the business of currency.
You may say that Bitcoin can be used to get money out of China, or into Brazil, or to enable shopping of “things that should not be called ‘drugs’ anyway”, but you have to admit that no matter what you think Continue reading
Syslog relay with Scapy
I needed to point some syslog data at a new toy being evaluated by security folks.Reconfiguring the logging sources to know about the new device would have been too much of a hassle for a quick test. Reconfiguring the Real Log Server (an rsyslog box) to relay the logs wasn't viable because the source IP in the syslog packets would have reflected the syslog box instead of the origin server.
A few lines of python running on the existing rsyslog box did the trick:
#!/usr/bin/env python2.7
from scapy.all import *
def pkt_callback(pkt):
del pkt[Ether].src
del pkt[Ether].dst
del pkt[IP].chksum
del pkt[UDP].chksum
pkt[IP].dst = '192.168.100.100'
sendp(pkt)
sniff(iface='eth0', filter='udp port 514', prn=pkt_callback, store=0)
This script has scapy collecting frames matching udp port 514 (libpcap filter) from interface eth0. Each matching packet is handed off to the pkt_callback function. It clears fields which need to be recalculated, changes the destination IP (to the address of the new Security Thing) and puts the packets back onto the wire.
The source IP on these forged packets is unchanged, so the Security Thing thinks it's getting the original logs from real servers/routers/switches/PDUs/weather stations/printers/etc... around the Continue reading
Configuring vPC on Cisco Nexus Devices
Today I am going to talk about the configurations of vPC on Cisco Nexus devices as i already talked about vPC in my earlier articles. If you want to have a look on the vPC basics check the below mentioned link for your references.
A short Story on vPC- Virtual Port Channel in Cisco Datacenter Environment
There are lot of questions how and why we are using the vPC in the Datacenter environment while some asked me about the difference in the vPC and VSS. Please have a look on the below link for the comparison of vPC and VSS.
Features comparison : Cisco vPC and Cisco VSS
Apart from the above mentioned articles, I wrote on the different technologies used by other vendors same as Cisco uses vPC and VSS. Below is the link defining the same
Feature Comparison: Juniper VCF vs HP IRF vs Cisco VSS vs Cisco vPC
From all the above articles, I think now you got the basics on vPC and VSS, but in this article I will talk about the vPC configuration in details with the diagram. The topology used in the article will be sample topology and has no relevance with any of Continue reading
A short Story on vPC- Virtual Port Channel in Cisco Datacenter Environment
There are lot of questions how and why we are using the vPC in the Datacenter environment while some asked me about the difference in the vPC and VSS. Please have a look on the below link for the comparison of vPC and VSS.
Features comparison : Cisco vPC and Cisco VSS
Apart from the above mentioned articles, I wrote on the different technologies used by other vendors same as Cisco uses vPC and VSS. Below is the link defining the same
Feature Comparison: Juniper VCF vs HP IRF vs Cisco VSS vs Cisco vPC
From all the above articles, I think now you got the basics on vPC and VSS, but in this article I will talk about the vPC configuration in details with the diagram. The topology used in the article will be sample topology and has no relevance with any of Continue reading
Things that cannot go wrong
Found this Douglas Adams quote in The Signal and the Noise (a must-read book):
The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair
I’ll leave to your imagination how this relates to stretched VLANs, ACI, NSX, VSAN, SD-WAN and a few other technologies.
Docker’s Kubernetes Support Leaves Questions Around Swarm
The company says it plans to evolve Swarm but hasn't provided any details.
SDxCentral’s Weekly News Roundup — November 10, 2017
Telstra and Ericsson complete 5G data call; SoftBank increases stake in Sprint; Edgecore Networks contributes hardware for white box packet transponder to TIP.
Lumina’s SDN Controller Manages Third Party Switches, Containers
This is targeted to the data center use case.
Verizon Makes SD-WAN Platform Available to its Wholesale Customers
The company's SD-WAN service is powered by Cisco Meraki.
Show 365: You Can’t Do That In Enterprise Networks
On today's show, Peyton Maynard-Koran joins the Packet Pushers talk about why some enterprise networks avoid change, and why vendors want to keep it that way. The post Show 365: You Can’t Do That In Enterprise Networks appeared first on Packet Pushers.
Cloudflare Wants to Buy Your Meetup Group Pizza
If you’re a web dev / devops / etc. meetup group that also works toward building a faster, safer Internet, I want to support your awesome group by buying you pizza. If your group’s focus falls within one of the subject categories below and you’re willing to give us a 30 second shout out and tweet a photo of your group and @Cloudflare, your meetup’s pizza expense will be reimbursed.
Developer Relations at Cloudflare & why we’re doing this
I’m Andrew Fitch and I work on the Developer Relations team at Cloudflare. One of the things I like most about working in DevRel is empowering community members who are already doing great things out in the world. Whether they’re starting conferences, hosting local meetups, or writing educational content, I think it’s important to support them in their efforts and reward them for doing what they do. Community organizers are the glue that holds developers together socially. Let’s support them and make their lives easier by taking care of the pizza part of the equation.
What’s in it for Cloudflare?
- We want web developers to target the apps platform
- We want more people to Continue reading
An Opinion On Offense Against NAT
It’s been a long time since I’ve gotten to rant against Network Address Translation (NAT). At first, I had hoped that was because IPv6 transitions were happening and people were adopting it rapidly enough that NAT would eventually slide into the past of SAN and DOS. Alas, it appears that IPv6 adoption is getting better but still not great.
Geoff Huston, on the other hand, seems to think that NAT is a good thing. In a recent article, he took up the shield to defend NAT against those that believe it is an abomination. He rightfully pointed out that NAT has extended the life of the modern Internet and also correctly pointed out that the slow pace of IPv6 deployment was due in part to the lack of urgency of address depletion. Even with companies like Microsoft buying large sections of IP address space to fuel Azure, we’re still not quite at the point of the game when IP addresses are hard to come by.
So, with Mr. Huston taking up the shield, let me find my +5 Sword of NAT Slaying and try to point out a couple of issues in his defense.
Relationship Status: NAT’s…Complicated
The first Continue reading
Introduction to Network Time Protocol (NTP) and Basic Configurations
Today I am going to discuss about the NTP or so called Network Time Protocol. I knew many of you already aware about the use of NTP in our networks but as it was asked by some guys who follow our blogs, So I am happy to explain the NTP little bit with the configurations.
What is Network Time Protocol or NTP ?
So, NTP is Network Time Protocol which is generally used to synchronise of the devices to some specific time references. NTP uses UDP protocol to communicate with all the devices in the network and all NTP communications in the network will be synchronised with the defined universal time in the network.
How they synchronise with the time source ?
NTP server usually receives its time from a trustworthy time source, such as a radio clock attached to a time server, and then distributes this time across the network. NTP is extremely efficient and there is no more than one packet per minute is necessary to synchronize two machines to within a millisecond of each other
An Network Time Protocol actually uses a layer to describe the distance between a network device and an authoritative time source
What is Network Time Protocol or NTP ?
So, NTP is Network Time Protocol which is generally used to synchronise of the devices to some specific time references. NTP uses UDP protocol to communicate with all the devices in the network and all NTP communications in the network will be synchronised with the defined universal time in the network.
How they synchronise with the time source ?
NTP server usually receives its time from a trustworthy time source, such as a radio clock attached to a time server, and then distributes this time across the network. NTP is extremely efficient and there is no more than one packet per minute is necessary to synchronize two machines to within a millisecond of each other
An Network Time Protocol actually uses a layer to describe the distance between a network device and an authoritative time source
- A layer 1 time server Continue reading
On the dangers of Intel’s frequency scaling
While I was writing the post comparing the new Qualcomm server chip, Centriq, to our current stock of Intel Skylake-based Xeons, I noticed a disturbing phenomena.
When benchmarking OpenSSL 1.1.1dev, I discovered that the performance of the cipher ChaCha20-Poly1305 does not scale very well. On a single thread, it performed at the speed of approximately 2.89GB/s, whereas on 24 cores, and 48 threads it performed at just over 35 GB/s.
CC BY-SA 2.0 image by blumblaum
Now this is a very high number, but I would like to see something closer to 69GB/s. 35GB/s is just 1.46GB/s/core, or roughly 50% of the single core performance. AES-GCM scales much better, to 80% of single core performance, which is understandable, because the CPU can sustain higher frequency turbo on a single core, but not all cores.
Why is the scaling of ChaCha20-Poly1305 so poor? Meet AVX-512. AVX-512 is a new Intel instruction set that adds many new 512-bit wide SIMD instructions and promotes most of the existing ones to 512-bit. The problem with such wide instructions is that they consume power. A lot of power. Imagine a single instruction that does the work of 64 regular Continue reading