networking | 易学教程

Access network in other docker container

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问题 I have two docker containers. The first has an OpenVPN server where multiple clients are connected. Now I want to reach one of the clients through the VPN from the other container (for example with a simple ping command). Is that possible? At the moment I linked the containers this way: version: '3' services: app: build: context: . dockerfile: app.dockerfile links: - ovpn:ovpn ovpn: build: context: . dockerfile: ovpn.dockerfile working_dir: /etc/openvpn privileged: true volumes: - ./openvpn:

how to send specific trap in lwip

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问题 I am new to SNMP, I am running SNMP v2 on an embedded device and want to send a trap when the system overheats. right now I have defined this in my mib file: dartTrapObjects OBJECT IDENTIFIER ::= {dart 2} dartTraps OBJECT IDENTIFIER ::= {dart 3} temp OBJECT-TYPE SYNTAX Integer32 MAX-ACCESS read-write STATUS current DESCRIPTION "Description for an integer" ::= {dartTrapObjects 1} overheat NOTIFICATION-TYPE OBJECTS { temp } STATUS current DESCRIPTION "A custom SNMPv2 trap" ::= {dartTraps 1} my

wlan网页登录认证原理

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解答一：它叫做 Captive portal ，请自行wiki 算了，还是简单说一下吧实现方法不止一种方案一 DNS跳转，把客户端所有的dns请求都解析为认证服务器的ip，然后认证服务器上有404跳转或者用dns url跳转，直接把dns解析为认证页面的地址方案二 http跳转，对所有的http请求返回302或者301跳转，目标是认证页面。在网关上就可以实现方案三 ip跳转，既把所有的ip包里的目标地址改为认证服务器，然后在认证服务器上做404跳转（因为用户有可能访问http://example.com/notexist这样在认证服务器上不存在的地址，所以需要404跳转），目标同样是认证页面，在网关上也可以实现（参考自知乎）解答二：有个东西叫做bas（broadband access sever）做控制，ac一般透传vlan到bas，由bas控制用户。用户需要在bas通过aaa，否则是不能上网的，即使你有貌似合法的ip。 WLAN用户接入流程流程描述： 1）用户通过标准的DHCP协议，通过AC获取到规划的IP地址。 2）用户打开IE，访问某个网站，发起HTTP请求。 3） AC截获用户的HTTP请求，由于用户没有认证过，就强制到Portal服务器。并在强制Portal URL中加入相关参数，具体请参见《中国移动WLAN业务PORTAL协议规范》。 4）

Cannot connect remotely to shiny-server and get R app working properly

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问题 I HAVE FIXED THIS ISSUE. Please read answer below I have installed shiny-server on Ubuntu 14.04.4 LTS with VirtualBox. After forwarding port 3838 in my router and setting a bridged network, then assigning a static IP to my virtual Ubuntu machine, I am being able to connect remotely, from a computer outside from my network and visualize the "hello" example app page, but only the HTML code is rendered. Both R and markdown iframes are not working (connection is reset and they are grayed). On the

Cannot connect remotely to shiny-server and get R app working properly

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Message-passing between all pods in a replica set

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问题 I'm writing an application to be deployed to Kubernetes where I want each pod to hold a TCP connection to all the other pods in the replica set so any container can notify the other containers in some use case. If a pod is added, a new connection should be created between it and all the other pods in the replica set. From a given pod, how do I open a TCP connection to all the other pods? I.e., how do I discover all their IP addresses? I have a ClusterIP Service DNS name that points to these

.Net UDP packet loss though all packets arrive (Wireshark) - ReceiveBuffer not the issue

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问题 This is the same question as C# UDP packetloss though all packets arrive (WireShark), except I do set ReceiverBuffer to 10MB, and I also monitor Socket.Available which shows the buffer doesn't even reach 200k utilization. In a simple test case, sending the same small (multicast) UDP packet (net data size: 137) 25,000 times using tcpreplay with at rate of 40Mbps, oftentimes not all packets arrive in my program, although all packets arrive in Wireshark, which I run at the same time on that box.

I cannot make UDP Ports work on a Windows Azure Virtual Machine

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问题 I cannot receive a UDP packet on a Windows Azure Virtual Machine. I have done the following: On the Virtual Machine, via Windows Firewall, I opened up Port 1234* both Inbound and Outbound for both UDP and TCP protocols. I did not add any IP exclusions. The rule should apply to Domain, Private and Public profiles. I am allowing Block Edge Traversal. In the Azure Management Portal, I added Endpoints for my Virtual Machine instance. I added both UDP and TCP protocol endpoints. Public and Private

What is the predictable behavior of changing SOL_SOCKET, SO_RCVBUF on the fly on a UDP socket?

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问题 What should be expected to happen if we resize the input buffer of a UDP server socket on the fly on a Linux system? setsockopt(sock, SOL_SOCKET, SO_RCVBUF, ...) I am particularly interested in these questions: If I shrink below what is currently in the buffer, would this simply drop the oldest/newest? datagrams properly, or could it flush everything that's there, or worse could it corrupt data such as truncating a datagram? Would shrinking the buffer even save memory or something prevents

C++ Sockets: Enabling Promiscuous Mode in Windows

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问题 I'm trying to modify my current socketing program to capture packets in promiscuous. What I currently have is able to capture packets normally. I've seen other answer for how to do this on Linux but I need to find a way to accomplish this on Windows. Here is my code: int main(int argc, char const *argv[]) { SOCKET s; //The bound socket struct sockaddr_in server; int recv_len; //Size of received data char udpbuf[BUFLEN]; //A buffer for the incoming data. float data; //The data in the packet /