Tag: dns

DNS global traffic scheduling

Background introduction With the rapid development of business, Company A is particularly concerned about the reputation and user experience of its products, and a good user experience is inseparable from the stable construction of infrastructure. Currently, Enterprise A has a single data center architecture. Due to the limitations of this architecture, after a data center […]

Set up a local DNS server

DNS resolution process: Taking the Linux system as an example, when the client needs to resolve the www.csdn.net domain name 1. First, the client will query the DNS cache in the browser (if DNS resolution is started from the browser), and if the query is successful, the corresponding IP address will be returned. 2. If […]

Tracing DNS query paths in Kubernetes

Follow the “Wonderful World of Linux” on the public account Set it as a “star” and let you play Linux every day! In past articles, we have traced network packets in Kubernetes [1], this article will trace DNS queries in Kubernetes. Let’s take the example of resolving the Service fully qualified domain name (FQDN) foo.bar.svc.cluster.local […]

[Docker] Docker-Compose built-in DNS load balancing failure problem

Docker Compose implements load balancing Let’s slightly modify the previous example docker-compose.yml: version: “3.8” services: flask-demo: build: context: . dockerfile: Dockerfile image: flask-demo:latest environment: – REDIS_HOST=redis-server – REDIS_PASS=${REDIS_PASS} healthcheck: test: [“CMD”, “curl”, “-f”, “http://localhost:5000”] interval: 30s timeout: 3s retries: 3 start_period: 40s depends_on: -redis-server deploy: replicas: 3 networks: -backend -frontend redis-server: image: redis:latest command: redis-server […]

autofs automatic mounting, DNS forward and reverse resolution-master-slave

1.nfs automatic mounting: upload, shared Operate on client Step 1: Preparation, uninstall manually mounted content [root@node1 ~]# umount /upload [root@node1 ~]# umount /shared [root@node1 ~]# mkdir /localdata/ [root@node1 ~]# yum install autofs -y Step 2: Modify the main mapping file and write information [root@node1 ~]# vim /etc/auto.master /localdata /etc/auto.localdata [root@node1 ~]# vim /etc/auto.localdata shared 192.168.118.129:/nfsdata/shared […]

Constructing DNS messages based on Scapy of Python3

One: DNS protocol DNS (Domain Name System) protocol is a basic protocol in computer networks. It is used to convert domain names (such as www.baidu.com) into IP addresses (such as 192.168.0.1) to achieve communication between computers. DNS is divided into query requests and query responses. The message structures of requests and responses are basically the […]

SSH (with experiment) + DNS (with experiment)

SSH remote connection management ssh comes with Linux. The default port number is 22. It has two main functions: remote login and remote replication. Connect remotely using the command: ssh -P 10086 [email protected] ssh: fixed start for establishing remote connection Root: Indicates logging in with the root account, so you need to enter the password […]

Installation and use of DNS stress testing tool-dnsperf (centos)

System tuning System tuning script, save as sh file, chmod and execute after elevating privileges #!/bin/sh #The maximum number of file handles allowed to be allocated globally in the system: sysctl -w fs.file-max=2097152 sysctl -w fs.nr_open=2097152 echo 2097152 > /proc/sys/fs/nr_open #The number of file handles allowed to be opened by the current session/process: ulimit -n […]

DNS covert tunnel tool–iodine traffic characteristic detection and analysis

Tool introduction Project address: https://github.com/yarrick/iodine Official website document: https://code.kryo.se/iodine Usage scenarios Iodine can create an IPv4 data channel through a DNS server, which is especially suitable for use in network environments where the target host can only send DNS requests. iodine is developed based on C language and is divided into server program iodined and […]