Tag Archives: layer4

Client IP persistence OR source IP hash load-balancing?

Client or Source IP ??? Well, this is roughly the same! Depends on people, environment, products, etc… I may use both of them in this article, but be aware that both of them points to the IP that is being … Continue reading

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Microsoft Exchange 2013 architectures

Introduction to Microsoft Exchange 2013 There are 2 types of server in Exchange 2013:   * Mailbox server   * Client Access server Definitions from Microsoft Technet website:   * The Client Access server provides authentication, limited redirection, and proxy services, and offers … Continue reading

Posted in Aloha, architecture, exchange, Exchange 2013, layer4, layer7 | Tagged , , , , , , | 5 Comments

load balancing, affinity, persistence, sticky sessions: what you need to know

Synopsis To ensure high availability and performance of Web applications, it is now common to use a load-balancer. While some people uses layer 4 load-balancers, it can be sometime recommended to use layer 7 load-balancers to be more efficient with … Continue reading

Posted in HAProxy, layer7, optimization | Tagged , , , | 4 Comments

Layer 4 load balancing tunnel mode

The tunnel mode looks like the Direct Server Return mode, except that traffic between the load-balancer and the server can be routed. The load-balancer encapsulates the request in an IP tunnel to the server. The server recover the client request … Continue reading

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layer 4 load balancing Direct Server Return mode

Direct server return is usually shortened to DSR. In DSR mode, the load-balancer routes packets to the backends without changing anything in it but the destination MAC address. The backends process the requests and answer directly to the clients, without … Continue reading

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Layer 4 load balancing NAT mode

NAT stands for Network Address Translation. In the NAT mode, the load-balancer will route traffic between user and server by changing destination IP address of the packets. TCP connection overview TCP connection is established between the client and the server. … Continue reading

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