从获取报文结果的分析软件能够看出,ICMP Reply报文的Checksum值有误,即图15-4中的incorrect代表Checksum值有误。 方法二: 在交换机上执行Ping操作的前后通过执行display icmp statistics命令查看bad checksum观察ICMP协议层面的Checksum错误包计数是否一直增长。
(0x00) Total Length: 60 Identification: 0x3c81 (15489) Flags: 0x00 0... ... = Reserved bit: Not set .0.. ... = Don't fragment: Not set ..0. ... = More fragments: Not set Fragment offset: 0 Time to live: 128 Protocol: ICMP (1) Header checksum: 0x0000 [incorrect, shoul...
Header checksum: 0xa8ae [correct] [Good: True] [Bad : False] Source: 10.0.0.100 (10.0.0.100) Destination: 192.168.0.1 (192.168.0.1) Internet Control Message Protocol Type: 8 (Echo (ping) request) Code: 0 () Checksum: 0x02f9 [incorrect,shouldbe 0xcae1] Identifier: 0xa01d Sequence num...
Checksum: 0x02f9 [incorrect, should be 0xcae1]Identifier: 0xa01dSequence number: 36096 (0x8d00)... 禁用ICMP 重定向 如果网络设计要求流量从进入交换机或路由器的同一第3层接口路由,则当您禁用对应的第3层接口上的ICMP重定向功能时,可以阻止流量通过CPU路由。 事实上,对于大多数网络,最好在所有第3层接...
The checksum field is used to validate ICMP messages. The sending system sets the value of the checksum field to 0 and performs a simple checksum operation. After running the checksum operation, the sending system puts the calculated checksum value in the checksum field. ...
Checksum code: 16 bits of data (from the start of the ICMP type) and then take the complement of it. In order to calculate the parity check code, the parity code field should be zero. These zeros will be replaced by check codes later. ...
Parameter problem. If a device detects an issue with the IP packet header, like invalid options or an incorrect checksum, it sends an ICMP Parameter problem message. What is ICMP used for? IP networks primarily use Internet Control Message Protocol for network traffic analysis. The following are...
checksum_value = checksum(header + data) header = struct.pack("bbHHh", icmp_type, icmp_code, checksum_value, pid, sequence) packet = header + data with socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_ICMP) as sock: sock.sendto(packet, (host, 1)) start_time = time....
ICMP Ping works by sending an ICMP packet that contains specific fields such as type, code, checksum, identifier, sequence number, and data. The 'type' field represents whether it's an echo request or reply message while the 'code' field specifies additional information about the message type...
Three fields of ICMP header follow the IP header. This provides an error categorizing code and a subcode field to refine the error code's definition and then a checksum. The first eight bytes of payload come from the ICMP sector, the transportation layer header (TCP or UDP). ...