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
A ‘router’ could be doing anything – particularly NAT, which might involve any amount of bug-ridden messing with traffic… One reason a device will send a RST is in response to receiving a packet for a closed socket. It’s hard to give a firm but general answer, because every possible perversion has been visited on … Read more
Active and passive are the two modes that FTP can run in. For background, FTP actually uses two channels between client and server, the command and data channels, which are actually separate TCP connections. The command channel is for commands and responses while the data channel is for actually transferring files. This separation of command … Read more
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
Starting with the release of Mosquitto version 2.0.0 (you are running v2.0.2) the default config will only bind to localhost as a move to a more secure default posture. If you want to be able to access the broker from other machines you will need to explicitly edit the config files to either add a … Read more
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
Your confusion lies in thinking that a socket is identified by Server IP : Server Port. When in actuality, sockets are uniquely identified by a quartet of information: Client IP : Client Port and Server IP : Server Port So while the Server IP and Server Port are constant in all accepted connections, the client … Read more
People say that the major thing TCP gives you is reliability. But that’s not really true. The most important thing TCP gives you is congestion control: you can run 100 TCP connections across a DSL link all going at max speed, and all 100 connections will be productive, because they all “sense” the available bandwidth. … Read more
This possible via Selenium WebDriver. For this you should do the following: Download selenium language-specific client drivers from – http://docs.seleniumhq.org/download/ and add apropriate jar files to your project build path. To run a test with Chrome/Chromium you will also need chromdriver binary which you can download from – http://chromedriver.storage.googleapis.com/index.html Create a test case like this: … Read more
It is true that a typical IPv4 header is 20 bytes, and the UDP header is 8 bytes. However it is possible to include IP options which can increase the size of the IP header to as much as 60 bytes. In addition, sometimes it is necessary for intermediate nodes to encapsulate datagrams inside of … Read more