the address of the remote host itself, the destination address is the IP address of the mobile host, in short, it is considered that the mobile host in the attribution network. In essence, it's the attribution agent. Using ARP proxy technology to use the attribution physical address to receive the data frame grouping on the link layer and then forward the packet to the field network where the mobile host resides.B. When sending information from a mobile host to a remote host, it is sent as norm
A Send a connection request and wait for confirmation
A, b
Established
Both establish a connection
The four-time handshake close link is as follows:The specific steps are as follows:1.A send fin message, Mark Seq=m2.B after receiving fin message, send confirmation message, Mark Seq=m+1Fin messages are also sent after 3.B, labeled Seq=n4.A after receiving fin message, send confirmation message, Mark Seq=n+1At this point the two sides are disconnected, and
; If (flags ~ (Sock_cloexec | sock_nonblock) Return-einval; Type = sock_type_mask; If (sock_nonblock! = O_nonblock (flags sock_nonblock) flags = (flags ~ Sock_nonblock) | o_nonblock; retval = sock_create (family, type, protocol, sock); // call sock_create to create a socket. The parameters are the protocol family number and socket type, the transport layer protocol
relationship, and BGP uses TCP to establish the adjacent relationship.Show commands related to BGP:Show ip bgp; displays the Routes learned by BGPShow ip bgp network; displays the BGP information of a specific networkShow IP neighbors; displays BGP neighbor InformationShow ip bgp peer-group; displays BGP peer group informationShow ip bgp summary; displays the summary of all BGP connectionsShow IP Route BGP; displays the BGP Route tableBGP-related debug commands:Debug ip bgp 192.1.1.1 updatesDeb
information of all connected Android devices, such as the device ID, With this ID we can specify the ID in the waitforconnection of the Monkeyrunner class to establish the connection between the Monkeyrunner background and the target Android machine when we write the script.
Figure 4-4-1 List all device information
ADB command-Specifies a device for communication: "Adb-s".As the information l
Schema hierarchyHTTPS (full name: Hypertext Transfer Protocol over secure Socket Layer) is a security-targeted HTTP channel and is simply a secure version of HTTP. That is, the SSL layer is added under HTTP, and the security base of HTTPS is SSL.SSL (secure Sockets layer Secure socket), and its successor Transport Layer Security (Transport layer Security,tls) is a security protocol that provides security an
' hwhandler= ' 0 ' WP=RW'-+-policy= ' round-robin 0 ' prio=1 status=active|-6:0:0:1 SDC 8:32 active ready Running # Here you can see that the devices are Active Status'-5:0:0:1 SDB 8:16 active ready Running # Here you can see that the devices are Active Statusanalog NIC failure, verifyingMultipathof theFailoverfunction# Ifdown Eth2 # wait a few seconds after execution to let DM confirm that the IP Path Down offDevice State:3 (Disconnected)# MULTIPATH-LLMar 17:12:21 |/etc/multipath.conf line, i
. For information on the first 236 bits, refer to the BOOTP protocol.4 DHCP of the Options Field
Option ID
Length (bytes)
Describe
1
4
Subnet Mask
3
N*4
Router (Gateway)
6
N*4
DNS
In the local area network, how to get the MAC address of the PPPoE server is a headache, especially in the Windows environment; There are two ways to get the PPPoE server MAC address:1. Under Windows, we run the Wireshark software, we can get all the packet format and content in and out of the network card, the Wireshark filter is set to PPPoE filter, and then the empty user name password dial, you can see the PPPoE discovery phase of 4 packets, Speci
maintenance. Similarly, in MINA and Netty, encoding and decoding must be inherited to implement the corresponding Encoder and Decoder, while in Twisted, Protocol is inherited to implement encoding and decoding. Although the implementation methods are different, their functions are the same:
1. Fit the message according to certain rules, such as fixed-length messages, specifying the Body length by line, separator, fixed-length headers, etc;
encountered---2, Information class Messages (Information message), also known as message messages , Highest bit to be 1, also ICMPv6 type=[128-255].NOTES: In the case of messages of the information class, the value of type is between 128-255 .Information-type messages (RFC2463), we use the most is type=128 echo request and 129, Echo reply.~~~~ Echo Request message (Echo Request)type=128, code=0.650) this.width=650; "Style=" background-image:none;bord
D. Fix a Tree time limit per test 2 seconds memory limit per test megabytes input standard input output standard OUTPU T
A Tree is an undirected connected graph without cycles.
Let's consider a rooted undirected tree with n vertices, numbered 1 through N. There is many ways to represent such a tree. One-is-to-create an array with n integers p1, p2, ..., pn, where Pi denotes a parent of vertex I (here, for C
and hardware types to determine the type of ARP packets such as hardware type 1 means to obtain the Hardware Address protocol IP refers to the to be mapped.IP address refers to IP addresses that map out interface addressesHardware size:6 length of hardware addressProtocol length of Size:4 protocol addressOpcode:request (1) ARP packet operation type 1 for ARP
very interesting, it receives the IP of the destination host, first sends a ttl=1 to the destination host (remember what TTL is?). UDP (the next to know what UDP is the packet), and after the first router receives the packet, the TTL is automatically reduced by 1, and the TTL becomes 0, the router discards the packet, and simultaneously produces a time-out ICMP datagram to the host. The host receives this datagram and sends a ttl=2 UDP datagram to th
after migrating a database to a new server through a restore or an attached form: 1. Identification: SELECT Dp.name, dp.sid from sys.database_principals DP left joins sys.server_principals sp on dp.sid = Sp.sid WHERE Sp.sid is NULL and dp.type_desc = ' sql_user ' and dp.principal_id > 4; 2. FIX: ALTER USER Fred with LOGIN =
host (Do you still remember what TTL is ?) After the first router receives the packet, the TTL is automatically reduced by 1 and the TTL is changed to 0, the router discards the packet and generates an ICMP datagram that is inaccessible to the host. After receiving the datagram, the host sends a UDP datagram with TTL = 2 to the target host, and then stimulates the second router to send an ICMP data report to the host. Until the target host is reached
sensitive in Java, the file name "Loading" in the Styles.xml definition must be lowercase.3. Files Styles.xml and loading.png are best placed in the root directory of the project file. Anyway, do not put in the root directory outside, its subfolders can be, folders in English, just build justice, do not want to trouble the best in English.4. Package the established 2 files in the installation file:①project
addresses over Ethernet, their values are 6 and 4, respectively.
The operation field indicates four operation types: ARP request (value: 1), ARP response (value: 2), and RARP request (value: 3) and RARP response (value: 4 ).
The following four fields are the sender's hardware address (in this example, the ethernet address), the sender's
discard the packet, and at the same time produce a host unreachable ICMP datagram to the host. The host receives this datagram and sends a ttl=2 UDP datagram to the destination host, then stimulates the second router to send ICMP datagrams to the host. This is repeated until the destination host is reached. In this way, traceroute gets all the router IPs. This avoids the problem that the IP header can only record limited routed IP.Someone asked, how
information is as follows:Reply from 10.4.24.1: bytes = 32 time Reply from 10.4.24.1: bytes = 32 time Reply from 10.4.24.1: bytes = 32 time Reply from 10.4.24.1: bytes = 32 time Ping statistics for 10.4.24.1:Packets: Sent = 4, stored ED = 4, Lost = 0 (0% loss ),Approximate round trip times in milli-seconds:Minimum = 0 ms, Maximum = 0 ms, Average = 0 msThe word ping is derived from the sonar location, and t
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