Is 0.0.0.0 a valid IP address?

It is valid inasmuch as it contains four octets, each within the range 0 through 255 inclusive. However, it is not usable as a real IP address. RFC1700 (a) states that 0.0.0.0/8 (0.<anything>.<anything>.<anything>) is reserved as a source address only. You can get into situation where it appears you have this address but that’s normally … Read more

How to expose docker container’s ip and port to outside docker host without port mapping?

You can accomplish this with IP aliasing on the host. First, add a virtual interface on the host that has a different IP address than the primary interface. We’ll call the primary interface eth0 with IP 10.0.0.10, and the virtual interface eth0:1 with IP address 10.0.0.11. ifconfig eth0:1 10.0.0.11 netmask 255.255.255.0 up Now run the … Read more

What is the cost of many TIME_WAIT on the server side?

Each socket in TIME_WAIT consumes some memory in the kernel, usually somewhat less than an ESTABLISHED socket yet still significant. A sufficiently large number could exhaust kernel memory, or at least degrade performance because that memory could be used for other purposes. TIME_WAIT sockets do not hold open file descriptors (assuming they have been closed … Read more

Maximum packet size for a TCP connection

The absolute limitation on TCP packet size is 64K (65535 bytes), but in practicality this is far larger than the size of any packet you will see, because the lower layers (e.g. ethernet) have lower packet sizes. The MTU (Maximum Transmission Unit) for Ethernet, for instance, is 1500 bytes. Some types of networks (like Token … Read more

How to connect to docker host from container on Windows 10 (Docker for Windows)

Short answer: in most cases, you’ll need 10.0.75.1 . In Docker for Windows, the container communicates through a vEthernet adapter called DockerNAT. To find its details, open Command Prompt and type ipconfig Look for an entry that looks like Ethernet adapter vEthernet (DockerNAT): Connection-specific DNS Suffix . : Link-local IPv6 Address . . . . … Read more