1. Use the lsof command line to list all open files
# lsof
This is a very long list, including open files and networks
The above screen contains many columns, such as PID, user, FD, and TYPE.
FD - File descriptor
The FD column contains such values.
cwd - Current working directorytxt - Text filemem - Memory Mapped filemmap - Memory Mapped deviceNumber - It represent the actual file descriptor. For example, 0u, 1w and 3r
R indicates read, w indicates write, and u indicates read/write.
Type indic
card reader mode. Ndef
Yesby Record (RTD,
Record )
The real user data is stored in RTD
. NFC Forum
Different RTD
Specification, such Text, Uri
, Signature
And so on. Note that P2P
And R/W
Is not shown in the figure Ndef
Specification.
Protocol bindings
, Here NFC Forum
Two specifications are proposed. One is: Obex
And the other is IP
The Protoco
: [7.111 MS] return time, here can also be found, a total of 3 time, remember? Traceroute sends three UDP packets each time. Note that the last column contains three addresses, which is not hard to understand, A vro will find a proper path based on the actual situation;3. Now let's take a look at the tcpdump collection results and observe the UDP packets sent by the Request Host.
18:56:27. 892318 IP (tos 0x0, ttl 1, id 10584, offset 0, flags [none], p
understand, A vro will find a proper path based on the actual situation;3. Now let's take a look at the tcpdump collection results and observe the UDP packets sent by the Request Host.
18:56:27. 892318 IP (tos 0x0, ttl 1, id 10584, offset 0, flags [none], proto UDP (17), length 60) 192.168.0.200.39914> 119.146.184.98.33434: [bad udp cksum 0xf19e-> 0 xfaae!] UDP, length 3218: 56: 27.892798 IP (tos 0x0, ttl
/etc/iproute2/rt_tables, you can manually edit the routing rules IP rule for routing, according to the routing rules to match, By priority (PREF) match from low to high until a suitable rule is found, it is necessary to configure the default route in the app.The IP rule show shows the routing rules.Add a route rule:# IP rule add from 192.168.1.10/32 table 1 pref 100If the pref value is not specified, it will be inserted before the existing rule minimum ordinalNote: After creating the routing rul
aggregates the subnet to subnet into a network segment: 128.213.64.0 with a mask of 255.255.224.0. Similarly, RTC aggregates the subnet to 128.213.127.0 into a network segment 128.213.96.0 with a mask of 255.255.255.224.0.
If Area 1 and Area 2 have overlapping CIDR blocks, it will be more difficult to aggregate, because after the aggregated address reaches Area 0, it will not know that the CIDR block is from Area 1, or Area 2.
Configure RTB as follows:RTB #Router ospfArea 1 range 128.213.64.0 2
measurement method. The specific implementation method is as follows:
· The mobile phone must measure the arrival measurement time (OTD value) of at least three base stations );
· Then, the mobile phone uploads the above OTD measured values to the smlc (serving mobile location center). smlc is generally placed in the BSC to complete location calculation;
· The LMU (location measurement unit) placed on the BTS side simultaneously measures the reference time of the base station (
, however, the next hop of this table item points directly to the S0 interface of RTA (for the reason, see the next hop attribute of BGP, RTE cannot directly go to the next hop of this route (because the routers RTD and RTC in the middle of the route do not go to the route 10.1.1.1/24, this is the case 。
So here, do smart readers understand? BGP emphasizes that the reason for synchronization is to ensure that the next hop can be reached. In the exampl
, and the network segments 20.1.1.1/32 and 20.1.1.2/32 converge into 20.1.1.0/24, so that when the ABR advertises to the backbone, it only advertises 20.1.1.0/ 24, suppress detail routing 20.1.1.1/32 and 20.1.1.2/32.Fault: Look at the RTA routing table, find that the route is incorrect, go to the detail segment of the route using the RTD as the next hop, the route to the Converged network segment uses RTB as the next hop, both exist simultaneously.650
PHP sends an email (PHPMailer details and usage instructions ). PHPMailer is also a powerful mail class PHPMailer main features: Support for mail smime-encrypted digital signatures support mail multiple TOs, CCs, BCCsandREPLY-TOs can work. PHPMailer is also a powerful mail class.
Main features of PHPMailer:
Supports mail s/mime-encrypted digital signatures
Supports email to multiple
possible status is: INVALID indicates that the package is an unknown connection, ESTABLISHED indicates a two-way transmission connection, and NEW indicates that the package is a NEW connection. Otherwise, the package is not transmitted in two directions, RELATED indicates that the package starts from a new connection, but is connected with an existing connection, such as FTP data transmission or an ICMP error.
UncleanThis module has no options, but it tries to match those strange and uncommon p
The basic strategy of Linux Policy Routing refers to the routing of IP packets based on the policies set by the network administrator. For example, we can have A policy like this: "select X path for all packages that come directly from Network A; select Y path for others", or "select path F for all packages whose TOS is; other selected paths K. Linux supports a maximum of 255 route tables, of which 3 are built-in: 255 Local route table (Local table) e
----------------------------------------------------- Define mppp and insert it into muppp group 1Ppp multilinkPpp multilink group 1!Interface Serial0/1/0Description IPLC to HQ S0/1/0 China CNC # L2025131Bandwidx 1984Ip address 10.254.251.2 255.255.255.252Ip accounting output-packetsEncapsulation pppLoad-interval 30Ppp multilinkPpp multilink group 1
After completion, it will be accompanied
Router VPN 10Network 10.254.250.0 0.0.3Network 10.254.250.4 0.0.0.3Network 10.254.251.0 0.0.3Network 192.1
Said the predecessors of PING Command. PING is used when the first Chinese hacker attacked Indonesia.
Ping Command details
I believe everyone is familiar with the ping command in Windows, but there are not many people who can make the most of the ping function, of course, I am not saying that I can allow ping to play its biggest function. I just often use the ping tool and summarize some small experiences. I would like to share it with you now.Now I will refer to the help instructions of the pin
algorithm of the temporary port is 204*256 + 73. To better understand the process, we have monitored the data transfer in this process. The following section describes how to use the client to log on to the temporary port.08/24-15:24:24. 052846 0: E0: 4C: F0: E0: Ea-> 0: D0: F8: 51: FC: 81 type: 0x800 Len: 0x4a192.168.10.8: 32791-> XXX. XXX: 52297 tcp ttl: 64 TOS: 0x0 ID: 39780 iplen: 20 dgmlen: 60 DF* ***** S * seq: 0x42206dd2 ack: 0x0 win: 0x16d0 t
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