good firewall

After minimizing the installation of CentOS7, many ports are not opened by default and need to be opened by Firewall-cmd.Check firewall status# firewall-cmd--staterunningShutting down the firewall# systemctl Stop firewalld# Firewall-cmd--Statenot runningView open Ports List#

In the previous article we have learned how to write some simple firewall rules, but these rules only take effect temporarily, when the firewall is shut down or the server shuts down, all the rules will be emptied after the reboot. So I need to save the written firewall rules so that after the firewall shuts down or re

Traditional firewalls are called border firewalls because they are deployed at the network boundary. The boundary firewall constitutes a barrier between the intranet and the external Internet, which is responsible for the network access control. Along with the development of the network security technology, the boundary firewall gradually exposes some weakness, which is embodied in the following aspects. L

First, what's the firewall doing?Anti-attack, optimize routing table, optimize network card delivery, filtering strategySecond, the firewall classificationFour layers: Network layer firewall, faster-"packet filter Firewall seven layer: Proxy layer Gateway Firewall, more secu

:04:42.155902 IP 192.168.110.69.7293 > 192.168.110.100.mcreport: UDP, length 112 However, the recvfrom of the socket cannot receive data. In addition, messages can be sent using the same tool in the virtual machine. Where is the problem? Because the socket is the code transplanted from other projects, I am worried that the Code may have bugs, so I checked it again and again to confirm that there is no problem. I also asked my boss to read it again, OK. I even suspected that there was a problem

In the past few days, the system has basically been done. After configuring the desktop (just personal preferences, desktop is dispensable, mainly for experience), with SSH remote logon, you can complete basic system settings. In the past few days, the system has basically been done. After configuring the desktop (just personal preferences, desktop is dispensable, mainly for experience), with SSH remote logon, you can complete basic system settings. Then we should note that the system is in the

You have accepted the idea of using a demilitarized zone (DMZ) to provide more secure and powerful protection for your machine, rather than simply using a traditional firewall in front of your entire network. This is good for you, but there is still a problem: will you use simple routing and set up a quarantine zone outside your single firewall? Or are there two firewalls and a quarantine zone between two f

You have accepted the idea of using a demilitarized zone (DMZ) to provide more secure and powerful protection for your machine, rather than simply using a traditional firewall in front of your entire network. This is good for you, but there is still a problem: will you use simple routing and set up a quarantine zone outside your single firewall? Or are there two firewalls and a quarantine zone between two f

Shutting down the firewall from the configuration menu is not working, simply do not install the firewall at the time of installationTo view the firewall status:/etc/init.d/iptables statusTo temporarily turn off the firewall:/etc/init.d/iptables stopPrevent firewalls from starting at system startup/sbin/chkconfig--leve

Shutting down the firewall from the configuration menu is not working, simply do not install the firewall at the time of installationTo view the firewall status:/etc/init.d/iptables statusTo temporarily turn off the firewall:/etc/init.d/iptables stopPrevent firewalls from starting at system startup/sbin/chkconfig--leve

The firewall in centos is a very powerful function, but it has been upgraded in the firewall in centos. Let's take a look at the usage of the firewall in centos in detail. Basic firewall operationsCommand Query the Firewall Status: [root @ localhost ~] # Service iptables st

The firewall under the Linux server is iptablesComponents, the Iptables firewall will block some of the necessary connections when installing some software.Viewing iptables Status: Service iptables statusIptables boot: On: Chkconfig iptables on off: Chkconfig iptables offiptables shutdown: On: Service iptables start Close: Service iptables stopRestart Firewall Se

Serv-u Firewall settingsToday friend asked a question, the firewall has set 21 port open, but the firewall opens, the FTP server is not connected. Using serv-u FTP Server software. I remember having encountered the same problem before, and then checking the data, finally turned over to the solution and shared the solution as follows: Set the allowed passive m

(i) Introduction to the firewall A firewall is a feature that protects an internal network or host by isolating the internal network from the external network or the Internet. A simple firewall can be performed by the ACL (Access control list) of the router,3 Layer switch, or it can be implemented with a single host, or even a subnet. Complex can be purchased by

install the Webmin System Management tool, you need to reconfigure the firewall, webmin the default port is 10000, according to the book tutorial set up the/etc/sysconfig/iptables file:[Email protected]/]#VI/etc/sysconfig/Iptables#firewall configuration written by System-config-firewall#manual Customization of thisfileis not recommanded.*filter:input ACCEPT [0:0

At present, there are many firewall products in the market, and the standard of dividing is quite miscellaneous. The main categories are as follows: 1. From soft and hardware form into Software firewalls and hardware firewalls, as well as chip-level firewalls. 2. From the firewall technology is divided into "Packet filter Type" and "Application agent type" two broad categories. 3. From the