The ultra-high port multiplexing of Netscaler helps to cope with the shortage of public network addresses.

People often ask whether it is necessary to increase the number of Ip addresses after migrating from Big-ip to Netscaler when an IP is only 65535 (regardless of the reserved port), especially in the application of link load balancing.

As we all know, Netscaler has obvious address saving characteristics compared with Big-ip. Basically, Netscaler can provide public network services with at least 2 public network addresses (management addresses are private network addresses) (NAT is on Netscaler rather than firewall), while Big-ip needs at least 4 public network addresses.

In the Big-ip environment, people will reserve a lot of Ip addresses to deal with insufficient ports, but in the Netscaler environment, a large number of public network addresses can be saved. Because of this characteristic, Netscaler content exchange function is given the possibility of IP carrying many services, and a single URL is implemented for the unified gateway function in the new version to provide a unified business interface for enterprises.

Netscaler's IP has the feature of ultra-high port multiplexing, and an IP can have millions of ports for TCP connections. The basic element of an socket is the SRC+S_Port+DST+D_Port+ protocol. Socket can be created as long as not all elements overlap at the same time.

Use the following command to see how many ports are available for SNIP:

Nsapimgr-d freeports

For example, query the number of ports available for each IP:

Root@netscaler01# nsapimgr-d freeports

Displaying all free ports of all MIPs...

Index IP FreePorts

0 0.0.0.1 16513804

1 127.0.0.2 1031695

2 241.0.0.2 1032112

3 241.0.0.4 1032112

4 241.0.0.5 16513792

5 10.0.1.52 1029948