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Questions tagged [ip-fragmentation]

44 questions
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How to read a pcap file generated by tcpdump that contains large UDP packets and reassemble the IP fragmented packets?

I would like to read a pcap file generated by tcpdump that contains large UDP packets that have undergone IPV4 fragmentation. The original packets are of a size of around 22000 bytes. In C++, I would use libtins with its IPV4Reassembler. Is there a…
Daniel
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Video streaming protocol - handling fragmentation

Recently i was trying to stream live video captured by webcam over udp. The approach I took was to read one frame,send it over udp and read the data at receiver side and display it. Now, I understand that sending data over udp/tcp results in…
DUDE_MXP
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How bad is ip fragmentation

I understand that when sending ip messages around, each hop in the network path between be and my packet's destination will check if the next hop's MTU is bigger than the size of the packet I sent. If so, the packet will be fragmented and the two…
Matteo Monti
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Will Socket deliver IP fragmented packets as one reassembled UDP packet?

When receiving TCP packets, Socket will give me reassembled packets, in case they got IP fragmented, as I'm guaranteed to get an ordered, gap-free stream of bytes. When receiving UDP packets, where I may receive packets in a different order than…
Evgeniy Berezovsky
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Clear Don't Fragment bit on Linux

I have a test requirement which required me clear don't fragment bit for packet flowing through Linux machine(cent-OS). I have tried setting the net.ipv4.ip_forward_use_pmtu=1 but it seems to only disable MTU Path discovery and does not clear DF…
Avinash Kumar Ranjan
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Disabling IP reassembly / defragmentation in link aggraegation scenario

The diagram below depicts a network that involves the aggregation of three slow channel throughputs over a WAN. Each router attempts to reassemble the fragmented IP packets which leads to data loss because the fragments take random paths through the…
George Robinson
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IPv6 reassembling

RFC8200 specifically says that fragmentation is done only by the source node and not by any intermediate node. It also says that fragments are reassembled at the receiver. Can I conclude from this that reassembly is done only at the receiver and no…
jt26
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Why doesn't Linux IPSec implementation support fragmentation before encryption?

I am trying to address an issue where ESP packets are getting fragmented as after adding the ESP header the MTU size is exceeded. The solution (which is what everybody does) is to do the fragmentation before doing the ESP encryption. My question is…
Nikhil Utane
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I can't fragment my packet on a TCP connection

I've been trying and trying to fragment my TCP packets but I havent found any helpful implementation of it. I am familiar with the theory and concepts of fragmentation, have even come across some flags such as IP_PMTUDISC_DONT, IP_PMTUDISC_WANT, and…
Awais Nawaz
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which data structure to choose for ip datagram reassembly at receiver end?

While reassembling datagram at receiver which data structure would be better in terms of if 1-2 fragment got lost we should discard complete datagram sorting of fragments should be faster if fragments are further fragmented then reassembling all…
anand
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Does the internet really works at 1500 bytes?

MTU (Maximum transmission unit) is the maximum frame size that can be transported. When we talk about MTU, it's generally a cap at the hardware level and is for the lower level layers - DataLink and Physical layer. Now, considering the OSI layer, it…
DUDE_MXP
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DF bit set for UDP socket program

I tried a simple code of UDP socket in Java and the analysis showed me that the DF bit was always set in the packet's IP Header, is there a way to clear the flag? I tried out a code in TCP as well, and both the server and client code was in the…
Anushreya
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IP Fragmentation on Linux

I have a linux system that sits between 2 routers ( sniffer like ). both routers support Jumbo frames while my system is limited to MTU 1500. My understanding that Sending router will fragment the Jumbo Frame into IP Datagram based on MTU 1500 and…
user3087632
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Extra Bytes in IP Fragmentation

I am currently going through my networking slides and was wondering if someone could help me with the concept of fragmentation so i understand the first part till "108 Bytes" but what I don't understand is this "8 Bytes = 13.5 => 13 * 8 Bytes =…
elGreato
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NodeJS ip fragmentation

This question suggests that the Node.js Net module doesn't handle ip-fragmentation: Node.js how to handle packet fragmentation with net.Server I can almost not imagine it's true, but I can't find any documentation about this (please forgive me if it…
Sander
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