2021年2月10日 · The size of a UDP header is 8 bytes. This means an IP packet with an empty UDP datagram as payload takes at least 28 (IPv4) or 48 (IPv6) bytes, but may take more bytes. Also note that in the case of Ethernet, the IP packet will additionally be wrapped in a MAC packet (14 byte header + 4 byte CRC) which will be embedded in an Ethernet frame (8 ...

2012年11月29日 · You are creating the socket as socket(AF_INET, SOCK_DGRAM, 0); meaning that it's a datagram (=UDP, typically) socket, so the network stack will automatically include IP header & UDP headers, etc. But since you are trying to create your own IP and UDP headers you must create a raw socket, then send the packet (and also calculate the checksum as ...

2016年12月30日 · The UDP header length field is the length of the UDP header plus the UDP data. It is indeed redundant since this length can be calculated from the IP header total length field where the UDP datagram length is the IP total length minus the IP header length.

To really use the line rate, through your UDP application, you will need to use/move to ethernet jumbo frames which may support upto 9000 bytes per frame. Also, if you look at netflix/youtube and other streaming protocols, they test your link before they start streaming.

2008年12月11日 · The UDP header itself specifies only the protocol port number. Thus, to verify the destination, UDP on the sending machine computes a checksum that covers the destination IP address as well as the UDP datagram. The pseudo-header is not transmitted with the UDP datagram, nor is it included in the length."

2012年2月16日 · If you are going for a fixed header, you assume that the first X bytes of every UDP message are metadata. You pick the X and it never changes per message. The recipient then knows to read X bytes as the header and all the rest as a message.

2018年6月4日 · UDP: Size of Ethernet frame - 24 Bytes Size of IPv4 Header (without any options) - 20 bytes Size of UDP header - 8 bytes. Total size of an Ethernet Frame carrying an IP Packet with an empty UDP Datagram - 24 + 20 + 8 = 52 bytes. EDIT: the above incorrectly states the ethernet frame bytes as 24B. It's instead 18 (or 22 for VLAN-tagged ethernet).

2014年7月22日 · The packet like you said, has the "payload" which is the data itself it needs to transfer (usually the user's data), the "header" contains various things depending on the protocol you are using, for example UDP contains just simple things in the header like Destination and Source IP/PORT, TCP on the other end contains more things like the sequence number of the …

2017年3月5日 · The maximal internet header is 60 octets, and a typical internet header is 20 octets, allowing a margin for headers of higher level protocols. That means you must subtract the IPv4 header length from the maximum of 65,535 to arrive at the maximum UDP datagram length, which includes the 8 octet UDP header.

2022年9月16日 · For examples of UDP rules that don't necessarily use the header, or that check for anomalous UDP packets, I recommend checking the existing Suricata Verify tests that have UDP rules, or the rule sets provided by Suricata and ET Open (those two should be made available via Suricata-update, which comes with Suricata, when you install it from ...