System Environment: CentOS 6.5Add an entry under the firewall file, but note the location of the entry;[Email protected]debris ~]# vi/etc/sysconfig/iptables# Firewall configuration written by System-config-firewall# Manual Customization of this file are not recommended.*filter: INPUT ACCEPT [0:0]: FORWARD ACCEPT [0:0]: OUTPUT ACCEPT [0:0]-A input-m state--state established,related-j ACCEPT-A input-p icmp-j ACCEPT-A input-i lo-j ACCEPT-A input-m state--state new-m tcp-p TCP--dport 22-j ACCEPT-A
Linux iptable firewall block and open ports
Source: http://hi.baidu.com/zplllm/item/f910cb26b621db57c38d5983
Evaluation:
1, close all the INPUT FORWARD OUTPUT only to some ports open.
Here is the command implementation:
Iptables-p INPUT DROP
Iptables-p FORWARD DROP
Iptables-p OUTPUT DROP
Then use the command iptables-l-N to see if it's set up and look good to all DROP
This setting is OK, we are only
Today, we will talk about how to use port ing without using the gateway to open the Intranet.
I. Prerequisites
A public IP address is required. Assume that we have a public IP Address: 210.210.21.21.
Ii. Tools used
1.lcx.exe
2. vdic
Iii. Methods
Method 1: Use lcx.exe for ing.
(1)we will upload lcx.exe to the public IP address, and execute lcx-listen Port 1
Today, we will talk about how to use port ing without using the gateway to open the Intranet.
I. Prerequisites
A public IP address is required. Assume that we have a public IP Address: 210.210.21.21.
Ii. Tools used
1.lcx.exe
2. vdic
Iii. Methods
Method 1: Use lcx.exe for ing.
(1)we will upload lcx.exe to the public IP address, and execute lcx-listen Port 1
The Oracle service port has many problems. The following describes how to open the Oracle service port on the firewall. It is helpful for you to learn about the Oracle service port.
To enable the Oracle client to connect to an Oracle server installed on windows with a firewall, it is not enough to
slightly. For example, the red Flag Asianux 3.0 SP1 Rescue CD version is available for use with only a subset of the parameters:Ref # Nc-h BusyBox v1.2.0 (2008.04.14-01:35+0000) multi-call binaryUSAGE:NC [OPTIONS] [IP] [port]Netcat opens a pipe to Ip:portOptions:-L Listen mode, for inbound connects-p port local port number- I SECS delay interval for lines SENT-
View the command Method for judging trojans on an open portCurrently, the most common Trojan Horse is based on the TCP/UDP protocol for communication between the client and the server. Since the two protocols are used, it is inevitable to open the listening port on the server side (that is, the machine where the trojan is planted) to wait for the connection. For
Open the Oracle service port on the firewall
To enable the Oracle client to connect to an Oracle server installed on windows with a firewall, it is not enough to open a 1521 or custom listening port.
Sometimes we need to map the port to remotely access the Oracle databas
Use Telnet IP port number to view port opening, how to judge by return value?
If the port is open, go directly to the port.
Enter the Telnet IP port number in cmd, and there will be two return results.
One is: connected to (IP)
emule is listening on two ports, starting with the 0.47c version it was randomly selected at the first start (previous versions used ports 4662 and 4672 by default), and you can see in the Options menu (see picture below) What Port emule has chosen. You can also modify those ports when you need them, and emule can work on any port.
Two ports, A is the TCP p
listening ports of the next three rows are UDP, so there is no State. Look! Port 7626 of my machine is open and listening is waiting for connection. In this case, it is very likely that it has been infected with glaciers! It is correct to quickly disconnect the network and Use anti-virus software to kill viruses.
2. fport, a command line tool working in Windows friends who use windows are better than tho
Differences between single-chip I/O port push-pull output and open-drain output)
Push-pull output: outputs high and low levels and connects to digital devices;
Open-drain output: the output end is equivalent to the collector of the transistor. To obtain a high-level state, the output end must be able to pull up the resistor. It is suitable for current-type driv
Today, I tested a program with a serial port in Linux. The prompt "open serial port: Permission denied" is displayed during execution.
Open_port: Permission denied
Environment: ubuntu12.04pl2303 USB to serial port
Later, I found this article on the Internet. It turns out that the user's permissions are insufficient. 1.
The connection to the host cannot be opened. when the project is started today on the port 1521: connection failure solution, a prompt is displayed that the remote Oracle cannot be connected. I tried to telnet port 1521 of the Oracle server, prompting that the connection failed. D: \ Documents ents and Settings \ Administrator> telnet 10.201.70.68 1521 www.2cto.com is connecting to 10.201.70.68... cannot
Port 80 cannot open the website. my website suddenly cannot be opened today and can be opened before. Today I checked and changed the port to another one. The website can be opened. If port 80 is used, it is not enabled. At first, I thought Port 80 was occupied. later, I fou
1. Run VSFTPD service First:#service vsftpd Start2. Open Port # 21st via Iptables(1) Check the iptables settings first:#iptables-NLChain INPUT (Policy ACCEPT)Target Prot opt source destinationACCEPT All – 0.0.0.0/0 0.0.0.0/0 State related,establishedACCEPT ICMP--0.0.0.0/0 0.0.0.0/0ACCEPT All--0.0.0.0/0 0.0.0.0/0ACCEPT TCP--0.0.0.0/0 0.0.0.0/0 state NEW TCP dpt:22REJECT All--0.0.0.0/0 0.0.0.0/0 reject-with i
Tags: Linux nmap port scan network segmentLinux generally does not automatically install NMAP commands using the Yum-y install nmap installation nmap command, provided that you have configured the Yum source.Nmap Features:Host detectionPort scanVersion detectionSystem detectionSupports the authoring of probe scripts
Nmap Command Detailed
nmapip_address #nmap默认发送一个arp的ping数据包 to detect all open
After opening the VSFTPD port, it is found that the client tool can log in, but cannot browse the files and create new files. At this point, I looked at the FTP protocol, and found that FTP has active mode and passive mode. Open port 21 on the server is to let the client come in, and do not go out of the port, also on
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