In the previous post VXLAN/EVPN – Host ARP, I talked about how knowing the MAC/IP of endpoints allows for ARP suppression. In this post we’ll take a look at host mobility. The topology used is the same as in the previous post:
Currently SERVER-1 is connected to LEAF-1. What happens if SERVER-1 moves to LEAF-2? This would be a common scenario for a virtual infrastructure. First let’s take a look at LEAF-4 on what routes we have for SERVER-1:
Leaf4# show bgp l2vpn evpn 0050.56ad.8506
BGP routing table information for VRF default, address family L2VPN EVPN
Route Distinguisher: 192.0.2.3:32777
BGP routing table entry for [2]:[0]:[0]:[48]:[0050.56ad.8506]:[0]:[0.0.0.0]/216, version 662
Paths: (2 available, best #2)
Flags: (0x000202) (high32 00000000) on xmit-list, is not in l2rib/evpn, is not in HW
Path type: internal, path is valid, not best reason: Neighbor Address, no labeled nexthop
AS-Path: NONE, path sourced internal to AS
203.0.113.1 (metric 81) from 192.0.2.12 (192.0.2.2)
Origin IGP, MED not set, localpref 100, weight 0
Received label 10000
Extcommunity: RT:65000:10000 ENCAP:8
Originator: 192.0.2.3 Cluster list: 192.0.2.2
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Take a Network Break! We start the new year by examining major themes and trends that we think will affect IT and networking in 2024. Topics include: AI beyond LLMs Whether open source can remain a viable model in a predatory tech environment Cisco vs. everybody Why IT can’t ignore geopolitics for strategic planning What... Read more »
Welcome to the sixteenth edition of Cloudflare’s DDoS Threat Report. This edition covers DDoS trends and key findings for the fourth and final quarter of the year 2023, complete with a review of major trends throughout the year.
What are DDoS attacks?
DDoS attacks, or distributed denial-of-service attacks, are a type of cyber attack that aims to disrupt websites and online services for users, making them unavailable by overwhelming them with more traffic than they can handle. They are similar to car gridlocks that jam roads, preventing drivers from getting to their destination.
There are three main types of DDoS attacks that we will cover in this report. The first is an HTTP request intensive DDoS attack that aims to overwhelm HTTP servers with more requests than they can handle to cause a denial of service event. The second is an IP packet intensive DDoS attack that aims to overwhelm in-line appliances such as routers, firewalls, and servers with more packets than they can handle. The third is a bit-intensive attack that aims to saturate and clog the Internet link causing that ‘gridlock’ that we discussed. In this report, we Continue reading
You may know Cloudflare as the company powering nearly 20% of the web. But powering and protecting websites and static content is only a fraction of what we do. In fact, well over half of the dynamic traffic on our network consists not of web pages, but of Application Programming Interface (API) traffic — the plumbing that makes technology work. This blog introduces and is a supplement to the API Security Report for 2024 where we detail exactly how we’re protecting our customers, and what it means for the future of API security. Unlike other industry API reports, our report isn’t based on user surveys — but instead, based on real traffic data.
If there’s only one thing you take away from our report this year, it’s this: many organizations lack accurate API inventories, even when they believe they can correctly identify API traffic. Cloudflare helps organizations discover all of their public-facing APIs using two approaches. First, customers configure our API discovery tool to monitor for identifying tokens present in their known API traffic. We then use a machine learning model Continue reading
Cloudflare DDoS 위협 보고서 제16호에 오신 것을 환영합니다. 이번 호에서는 2023년 4분기이자 마지막 분기의 DDoS 동향과 주요 결과를 다루며, 연중 주요 동향을 검토합니다.
DDoS 공격이란 무엇일까요?
DDoS 공격 또는 분산 서비스 거부 공격은 웹 사이트와 온라인 서비스가 처리할 수 있는 트래픽을 초과하여 사용자를 방해하고 서비스를 사용할 수 없게 만드는 것을 목표로 하는 사이버 공격의 한 유형입니다. 이는 교통 체증으로 길이 막혀 운전자가 목적지에 도착하지 못하는 것과 유사합니다.
이 보고서에서 다룰 DDoS 공격에는 크게 세 가지 유형이 있습니다. 첫 번째는 HTTP 서버가 처리할 수 있는 것보다 더 많은 요청으로 서버를 압도하여 서비스 거부 이벤트를 발생시키는 것을 목표로 하는 HTTP 요청집중형 DDoS 공격입니다. 두 번째는 라우터, 방화벽, 서버 등의 인라인 장비에서 처리할 수 있는 패킷보다 많은 패킷을 전송하여 서버를 압도하는 것을 목표로 하는IP 패킷집중형 DDoS 공격입니다. 세 번째는 비트 집중형 공격으로, 인터넷 링크를 포화 상태로 만들어 막히게 함으로써 앞서 설명한 '정체'를 유발하는 것을 목표로 합니다. 이 보고서에서는 세 가지 유형의 공격에 대해 다양한 기법과 인사이트를 중점적으로 다룹니다.
보고서의 이전 버전은 여기에서 확인할 수 있으며, 대화형 허브인Cloudflare Radar에서도 확인할 수 있습니다. Cloudflare Radar는 전 세계 인터넷 트래픽, 공격, 기술 동향, 인사이트를 보여주며, 드릴 다운 및 필터링 기능을 통해 특정 국가, 산업, 서비스 공급자에 대한 인사이트를 확대할 Continue reading
SPSS（Source Port Service Sweep）プロトコルを悪用したフラッドは、多数のランダムまたは偽装されたソースポートから、標的となるシステムやネットワーク上のさまざまな宛先ポートにパケットを送信するネットワーク攻撃手法です。この攻撃の目的は2つあります。1つ目は、被害者の処理能力を圧倒し、サービスの中断やネットワークの停止を引き起こすこと、2つ目は、オープンポートをスキャンし、脆弱なサービスを特定することです。フラッドは大量のパケットを送信することで実現され、被害者のネットワークリソースを飽和させ、ファイアウォールや侵入検知システムの能力を使い果たします。このような攻撃を軽減するためには、インラインの自動検知機能を活用することが不可欠です。
When I published the Bidirectional Route Redistribution lab exercise, some readers were quick to point out that you’ll probably have to reuse the same AS number across multiple sites in a real-life MPLS/VPN deployment. That’s what you can practice in today’s lab exercise – an MPLS/VPN service provider allocated the same BGP AS number to all your sites and expects you to deal with the aftermath.
When I published the Bidirectional Route Redistribution lab exercise, some readers were quick to point out that you’ll probably have to reuse the same AS number across multiple sites in a real-life MPLS/VPN deployment. That’s what you can practice in today’s lab exercise – an MPLS/VPN service provider allocated the same BGP AS number to all your sites and expects you to deal with the aftermath.
Autonomous Digital Experience Management (ADEM) provides detailed visibility into end user device and application performance. On today’s sponsored episode, we talk with Palo Alto Networks about how it uses AIOps with ADEM to help IT and help desk teams quickly identify and respond to problems for a distributed workforce. We also discuss synthetic transactions, and... Read more »
One of the roles of Cloudflare's Observability Platform team is managing the operation, improvement, and maintenance of our internal logging pipelines. These pipelines are used to ship debugging logs from every service across Cloudflare’s infrastructure into a centralised location, allowing our engineers to operate and debug their services in near real time. In this post, we’re going to go over what that looks like, how we achieve high availability, and how we meet our Service Level Objectives (SLOs) while shipping close to a million log lines per second.
Logging itself is a simple concept. Virtually every programmer has written a Hello, World! program at some point. Printing something to the console like that is logging, whether intentional or not.
Logging pipelines have been around since the beginning of computing itself. Starting with putting string lines in a file, or simply in memory, our industry quickly outgrew the concept of each machine in the network having its own logs. To centralise logging, and to provide scaling beyond a single machine, we invented protocols such as the BSD Syslog Protocol to provide a method for individual machines to send logs over the network to a collector, providing a single pane of glass Continue reading
In the last post Advertising IPs In EVPN Route Type 2, I described how to get IPs advertised in EVPN route type 2, but why do we need it? There are three main scenarios where having the MAC/IP mapping is useful:
Host ARP.
Host mobility.
Host routing.
In this post I will cover the first use case and the topology below will be used:
Host ARP
When two hosts in the same subnet want to send Ethernet frames to each other, they will ARP to discover the MAC address of the other host. This is no different in a VXLAN/EVPN network. The ARP frame, which is broadcast, will have to be flooded to other VTEPs either using multicast in the underlay or by ingress replication. Because the frame is broadcast, it will have to go to all the VTEPs that have that VNI. The scenario with ingress replication is shown below:
In this scenario, SERVER-1 is sending an ARP request to get the MAC address of SERVER-4. As all leafs are participating in the L2 VNI, LEAF-1 will perform ingress replication and send it to all leafs. However, sending the ARP request to LEAF-2 and LEAF-3 is not needed Continue reading
While InfiniBand is making gains, many enterprises are sticking with Ethernet for their data center switching and interconnectivity needs to run their AI workloads.
Investment in supercomputing and related HPC technologies is not just a sign of how much we are willing to bet on the future with someone else’s money, but how much we believe in it ourselves, and more importantly, how much we believe in the core idea that we can predict and therefore shape the future of the world. …
At the start of each year, I’ve been reporting on the behaviour of the Internet’s inter-domain routing system over the previous 12 months, looking in some detail at some metrics from the routing system that can show the essential shape and behaviour of the underlying interconnection fabric of the Internet. The year 2023 marks a significant point in the evolution of the Internet where the strong growth numbers that were a constant feature of the past thirty years are simply not present in the data. Not only is the Internet’s growth slowing down significantly, but in the IPv4 network it appears to be shrinking, which is unprecedented in the brief history of the Internet to date.
At the start of each year, I’ve been reporting on the behaviour of the Internet’s inter-domain routing system over the previous 12 months, looking in some detail at some metrics from the routing system that can show the essential shape and behaviour of the underlying interconnection fabric of the Internet. The year 2023 marks a significant point in the evolution of the Internet where the strong growth numbers that were a constant feature of the past thirty years are simply not present in the data. Not only is the Internet’s growth slowing down significantly, but in the IPv4 network it appears to be shrinking, which is unprecedented in the brief history of the Internet to date.
