traceroute gateway

Application of ICMP--tracerouteTraceroute is an important tool to detect the routing between host and destination hosts, and is also the most convenient tool. As mentioned earlier, although the Ping tool can also detect, however, because of the IP header limit, ping can not be fully recorded under the router. So the traceroute just fills this flaw.The principle of traceroute is very very interesting, it rec

Role:A router, gateway that looks at which IP addresses the packet passed through during transmission.Working principle:First send a TTL of 1 UDP packets to the remote host, according to the protocol, the router receives the packet, the TTL value minus 1, when the TTL is 0, the router discards the packet, and sends the sender back an ICMP packet, the packet contains the router's own IP address. Similarly, the host that executes the

Android.view.view;import Android.widget.edittext;import android.widget.textview;/** can not understand the annotation I eat half a kilo of dog food:-) */public class Mainactivity extends actionbaractivity {private EditText et_cmd;private String app_path;private TextView tv_result; @Overrideprotected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate); Setcontentview (r.layout.home_activity); * Initialize Control */et_cmd = (EditText) Findviewbyid (r.id.et_cmd); tv_res

1. traceroute can be used to query routes from one host to another. 2. Principles PingProgramA record routing option is provided, but not all hosts support this option, and the IP header option field can only store up to nine IP addresses. Therefore, it is necessary to develop traceroute.Traceroute uses the TTL fields of the ICMP message and IP header. TTL is an 8-bit field, which is the router's hop counter and also indicates the datagram lifecyc

returns an ICMP inaccessibility packet, and sets the combination of the type and code in the packet to port inaccessibility. The Traceroute program generates ICMP error packets by using port unavailability. In addition, in most cases, an ICMP error message is generated when an error occurs when an IP datagram is transmitted, but the following situations do not cause an ICMP error message: * ICMP error messages do not generate error messages (ICMP que

.tracerouteTraceroute also uses the ICMP protocol, which uses ICMP for more time than error-Error reporting and ICMP endpoint unreachable messages. For the ICMP protocol, the principle is:Important options for traceroute are:[Plain]View PlainCopy -u--uses the UDP protocol to detect, which is the default detection protocol. -i--uses the ICMP protocol to detect -t--uses the TCP protocol to detect Examples of use are:[Plain]View Pla

The previous two articles "Linux Common Network Tools: Fping host Scan" and "Linux common Network Tools: hping Advanced Host Scan" are all about the host scan, this article introduces the common route scanning tools traceroute and MTR.A route scan is primarily a query for the number of hops and data delays that are routed to another host.Traceroute Basic Use The principle of the route scanning tool is the time to live (TTL) to achieve. Each time

/bashif ["$#"-ne 1];then echo "Usage-/ping.sh [interface]" echo "excample-./ping.sh 192.168.1.0" echo "Example would perform an ARP scan of the The local subnet to which eth0 are assigned" exitfiprefix=$ (echo $ | cut-d '. '-f 1-3) for addr in $ (SEQ 1 254);d o ping-c 1 $prefix. $addr | grep "bytes from" | cut-d ""-F 4 | Cut-d ":"-F 1done 2. Traceroute route Tracking Not only can we find out if the target m

length)PTR is called a pointer field. He is a pointer based on 1, he points to the location of the next IP address, his minimum value is 4, point to the location of the first IP address, with each IP address into the list, PRT values are 8, 12 Max to 36. When 9 IP addresses are recorded, the value of PTR is 40, indicating that the manifest is full.Traceroute ProgramThe Traceroute program allows us to see the routes that the IP datagram passes from th

Ping programThe ping program was written by Mike Muuss to test whether another host is available.The program sends an ICMP echo request message to the main clause and waits for an ICMP echo reply to be returned.The ping program can also detect the return time of this hostTraceroute ProgramThe Traceroute program is a handy tool to explore the TCP/IP protocol in more depthThe Traceroute program allows us to s

Principles of Ping and Traceroute (5) (Reference) TCP/IP explanation, Volume 1: Protocol The name "ping" comes from the sonar positioning operation. The purpose is to test whether another host can arrive. The program sends an ICMP echo request packet to the host, and waits for the returned ICMP echo response. Generally, if you cannot ping a host, you cannot Telnet or FTP to the host. In turn, if you cannot Telnet to a host, you can usually use the pi

traceroute the principle of:1.traceroute host to be Trace Host Send UDP The destination port is a port with a large number (for example, 33434 Port)2. First package ttl= 1 Span style= "Font-family:simsun;" lang= "ZH-CN" xml:lang= "ZH-CN", dport=33434 ; future packet ttl 1 3. How to determine that you have reached your destination,general destinations are not UDP 33434 this large port to open wha

tcp-m tcp--dport 22-j DROP-A output-m conntrack--ctstate new-j ACCEPTCOMMIT# completed on Fri Dec 19 17:01:18 2014It has been noted that:-A input-j DROP--------------------------------------->ping is output;traceroute when each routing node returns the packet;The rule-a output-m conntrack--ctstate new-j Accept is the TCP protocol by default, whereas the Ping/traceroute uses the ICMP protocol;-A input-p tcp

Command name: PingFunction: Test network connectivityCommand path:/bin/pingUsage: ping [-c] IP addressParameters:-C specify number of times to sendCommand name: ifconfigFunction: View and set network card information (temporary settings)Command path:/sbin/ifconfigUsage: ifconfig [NIC name] [IP Address]Example:Ifconfig eth0 192.168.1.1Command name: tracerouteFunction: Displays the path between the packet and the target host and the time consumed by each nodeCommand path:/bin/tracerouteUsage: