OSPF(IP) 89 DR sends routing updates 224.0.0.5 Non-DR/BDR sends LSA updates 224.0.0.6 Internal 10 External 150
RIP(UDP) port520 Update 30S, aging 180S, recycling 120S Multicast 224.0.0.9 Priority 100
RIPng port521 IPV6 RIP
BGP(TCP) port179 priority 255
isis 15
GRE protocol number 47
telnet port23
SSH port22
HTTP port80
HTTPs port443
TCP protocol number 6
UDP protocol number 17
FTP control 21 data 20
TFTP 69
DNS 53
3389 port remote login
DHCP port number 67 68
AH IP protocol 51
MTU======IP [Layer 3] header + data field
0x0806 ARP
0x0800 IPV4
0x8100 VLAN
0x8847 mpls
802.1q vlan
802.1x security authentication
802.1ac wireless
802.1b wireless channel
multicast address
PIM 224.0.0.13
VRRP 224.0.0.18
IGMPv3 224.0.0.22
568b 1, 2, 4, 6 transmission
Virtual interface vlan null0 loopback subinterface tunnel
General MTU 1514
standard data frame 14B
Ping parameter
-a ip-address: Set the source IP address of sending ICMP ECHO-REQUEST message, this address must be the local interface IP address.
-c: count is the number of ICMP ECHO-REQUEST messages sent, ranging from 1 to 4294967295, and the default is 5 times.
-d: Set the socket to DEBUGGING mode, the default is non-DEBUGGING mode.
-f: When the data packet length is greater than the interface MTU, it will not be fragmented and will be discarded.
-h ttl: Specify the TTL value in the ICMP ECHO-REQUEST packet, ranging from 1 to 255. The default is 255.
-i interface-type interface-number: Specify the type and number of the interface that sends ICMP ECHO-REQUEST packets. After specifying this parameter, the ttl value of the message is automatically set to 1 to test directly connected devices (that is, the IP address of the device and the IP address of the specified interface are in the same network segment).
ip: Configure the device to support the IPv4 protocol. By default, the device supports the IPv4 protocol.
-n: The host parameter is directly used as an IP address without domain name resolution; by default, host is first used as an IP address, and if it is not an IP address, domain name resolution is performed.
-p: pattern is the filling byte of ICMP ECHO-REQUEST message, the format is hexadecimal. For example, -p ff will fill all the message with ff. The default filling method is to start from 0x01 and gradually increase until 0x09. repeat.
-q: Except statistics, no other detailed information is displayed, and all information including statistics are displayed by default.
-s packetsize: ICMP ECHO-REQUEST message length (excluding IP and ICMP message header), in bytes, the value range is 20 to 32000, and the default message length is 56 bytes.
-t timeout: After sending ICMP ECHO-REQUEST, wait for the timeout time of ICMP ECHO-REPLY, in ms, the value range is 0～65535, the default timeout time is 2000ms.
-tos tos: Specifies the ToS value in the ICMP ECHO-REQUEST packet, the value range is 0 to 255. The default is 0.
-v: Display the received ICMP messages other than ECHO-REPLY; by default, other non-ECHO-REPLY ICMP messages are not displayed.
host: The domain name or IP address of the destination host.
1. The client broadcasts a dhcp-discovery message and asks where the server is
. 2. After the server receives it, it broadcasts a dhcp-offer message to an address
. 3. After the client receives it, it broadcasts a dhcp request message. I will use your ip Address
4. The server broadcasts the ACK after receiving the request.
5. Use the ip address.
Another: If you receive multiple offers, when you choose the first one to
send the request, it also broadcasts that I have the address given by the server