Apcela Preps for What’s Next with Funding and New President
Its product overlays application delivery and monitoring on SD-WANs from Cisco and Versa Networks.
U.S. Congressman Bashes ZTE and Huawei in New Bill
The bill would prohibit the U.S. government from buying from the companies.
Network Break 167: Meltdown & Spectre Strike; Oracle CEO Predicts IT Shakeout
Listen to this week Network Break as we examine the Meltdown and Spectre vulnerabilities, Oracle CEO Mark Hurd's remarks about the disruption of traditional IT & more tech news. The post Network Break 167: Meltdown & Spectre Strike; Oracle CEO Predicts IT Shakeout appeared first on Packet Pushers.Can IPv4 Networks Be Compromised via IPv6?
The Fox-IT International Blog recently published an article on how IPv4 networks can be compromised via IPv6. The attack vector relies on the default IPv6 configuration in the Windows operating system to spoof DNS replies by acting as a malicious DNS server to redirect traffic to an attacker-specified endpoint. The Windows Proxy Auto Discovery (WPAD) feature can also be exploited in order to relay credentials and authenticate to various services within the network, using a tool called called mitm6 created by Fox-IT.
Fox-IT is recommending that IPv6 is disabled when it is not being used, as disabling Proxy Auto Detection. This of course means that Windows-based hosts are unable to switch preference to IPv6 when it is available (which all versions since Windows Vista will do), and that IPv6 would need to be explicitly re-enabled on hosts.
The article makes some important points, but IPv4 and IPv6 are fundamentally incompatible on a wire level and it needs to be understood they can’t communicate with each other except through translation devices. There are a number of known issues (including this one) with the security of automatic configuration mechanisms running on Local Area Networks, both under IPv6 and IPv4, but these require physical access to Continue reading
SYN packet handling in the wild
Here at Cloudflare, we have a lot of experience of operating servers on the wild Internet. But we are always improving our mastery of this black art. On this very blog we have touched on multiple dark corners of the Internet protocols: like understanding FIN-WAIT-2 or receive buffer tuning.
CC BY 2.0 image by Isaí Moreno
One subject hasn't had enough attention though - SYN floods. We use Linux and it turns out that SYN packet handling in Linux is truly complex. In this post we'll shine some light on this subject.
The tale of two queues
First we must understand that each bound socket, in the "LISTENING" TCP state has two separate queues:
- The SYN Queue
- The Accept Queue
In the literature these queues are often given other names such as "reqsk_queue", "ACK backlog", "listen backlog" or even "TCP backlog", but I'll stick to the names above to avoid confusion.
SYN Queue
The SYN Queue stores inbound SYN packets[1] (specifically: struct inet_request_sock). It's responsible for sending out SYN+ACK packets and retrying them on timeout. On Linux the number of retries is configured with:
$ sysctl net.ipv4.tcp_synack_retries
net.ipv4.tcp_synack_retries = 5
Meltdown and Its Networking Equivalents
One of my readers sent me this question:
Do you have any thoughts on this meltdown HPTI thing? How does a hardware issue/feature become a software vulnerability? Hasn't there always been an appropriate level of separation between kernel and user space?
There’s always been privilege-level separation between kernel and user space, but not the address space separation - kernel has been permanently mapped into the high-end addresses of user space (but not visible from the user-space code on systems that had decent virtual memory management hardware) since the days of OS/360, CP/M and VAX/VMS (RSX-11M was an exception since it ran on 16-bit CPU architecture and its designers wanted to support programs up to 64K byte in size).
Read more ...Salt From The Start To The Beginning
Salt quick start guide.Salt From The Start To The Beginning
As described by their website; Salt is "Event-driven automation for a software-defined world". You gotta love marketing :) Salt is a large project with many features including; configuration management, an event based reactor, cloud management and network automation. Salt can do ALOT but...NSX-T: OpenAPI and SDKs
Nowadays everything is about automation. Organizations are moving away from the traditional static infrastructure to full automation and here the need of NSX is significant. There are many use-cases for NSX, but the common in all of them is that they all need to be automated.
VMware is investing heavenly for different tools to ease the automation aspect of NSX but in order to take full advantage of it one need to understand what happens under the hood. It is also important if someone wants to build their own custom automation tool or CMP (Cloud Management Platform). Many existing solutions like Openstack, Kubernetes, vRO and so on automate NSX-T using different plugins. In fact, those plugins are sending REST API calls to NSX Manager in order to automate logical topology CRUD(Create, Read, Update, Delete) operations.
Based on our experience we decided that NSX-T APIs will be based on JSON format following OpenAPI standard. The use of Open APIs is to enable third party developers to build applications and services around NSX-T by standardising on how REST APIs are described. This means one can use standard tools like Swagger to read and use those APIs. Below is a quick example from my Mac on Continue reading
Worth Reading: Robust IPAM
Elisa Jasinska covered several IPAMs in her overview of open-source network automation tools, and we had Jeremy Stretch talking about NetBox in the Building Network Automation Solutions online course, but if you’re looking for a really robust easy-to-implement solution, check out this document from 1998 (deployment experience, including a large-scale one).
Deleting Checkpoint Logs
The directories that need to be emptied to delete all the logs on the Checkpoint managers.
Checkpoint Identity Awareness
The 3 main elements that run identity awareness under the hub are Active Directory Query (ADQ), PDP and PEP. They all intertwine in some way to allow the different blades of the Checkpoint to track and restrict access based on AD user and machine name. I tested these features as part of a POC and personally I would not consider them fit for purpose in a production environment. See the caveats at the end of the post for more details on this.
ParkMyCloud Automates Multi-Cloud Cost Control
The platform works with AWS, Azure, and Google, and plans to support Alibaba Cloud later this year.
NSX-T: Routing where you need it (Part 2, North-South Routing)
In the first part of this blog series, NSX-T: Routing where you need it (Part 1), I discussed how East-West (E-W) routing is completely distributed on NSX-T and how routing is done by the Distributed Router (DR) running as a kernel module in each hypervisor.
In this post, I will explain how North-South (N-S) routing is done in NSX-T and we will also look at the ECMP topologies. This N-S routing is provided by the centralized component of logical router, also known as Service Router. Before we get into the N-S routing or packet walk, let’s define Service Router.
Service Router (SR)
Whenever a service which cannot be distributed is enabled on a Logical Router, a Service Router (SR) is instantiated. There are some services today on NSX-T which are not distributed such as:
1) Connectivity to physical infrastructure
2) NAT
3) DHCP server
4) MetaData Proxy
5) Edge Firewall
6) Load Balancer
Let’s take a look at one of these services (connectivity to physical devices) and see why a centralized routing component makes sense for running this service. Connectivity to physical topology is intended to exchange routing information from NSX domain to external networks (DC, Campus or Continue reading