Questions tagged [ip-fragmentation]
The ip-fragmentation tag has no usage guidance.
23
questions
1
vote
0
answers
129
views
Will the raw table ever receive fragmented IP packets?
Assume the conntrack module is loaded (thus nf_defrag_ipv4 is loaded). Will there ever be a situation in which the raw table receives a fragmented packet? In particular, will a BPF rule (loaded ...
- 462
1
vote
1
answer
658
views
forwarded TCP traffic is refragmented on Linux despite the "Don't fragment" flag
We have 2 VPN servers at the same hoster. The servers are virtual and they have different Linux distros. The VPN clients establish https connections to the same Amazon EC2 server. The TCP packets from ...
- 558
0
votes
0
answers
244
views
IPv4 fragmentation and high speed data
Please excuse me if this has been answered before, but I couldn't easily find an answer.
My company creates high-speed measurement equipment, that produces roughly 0.7 Gigabit/second of UDP data. Each ...
- 101
0
votes
0
answers
301
views
When is maximum IP fragmentation offset used?
The IP fragmentation offset has length 13 bits. Max offset is 2^13-1 = 8191.
I want to ask if the following packet sequence can create a total IP packet exceeding its max length, then under what ...
- 145
1
vote
0
answers
1k
views
How to selectively disable IP reassembly?
The diagram below depicts a scenario that involves aggregation of three slow channel throughputs over a WAN.
A fast host on a WAN (@ 54.239.98.8) is communicating with a host on a LAN (@ 192.168.0.100)...
- 155
0
votes
0
answers
511
views
TCP Retransmissions when packets exceed 1500+
I am currently trying to communicate using NMOS protocol over my network. This is a /30 network.
The issue I am seeing is that when I send an http request from my computer to my device over the ...
- 115
2
votes
0
answers
680
views
Forwarding Fragments with IPTables / FirewallD
I have a linux (openSuse Leap 15.0) computer that's connected to a cable modem using PPoE (hopefully not relevant to this. EDIT the ppp0 interface has an mtu of 1492 but the eth0 interface it is "...
- 121
0
votes
1
answer
3k
views
RDP connections failing under specific circumstances
Problem
RDP connections from PCs or servers in both branch sites to the RDSH server in the main site are intermittently failing with the following error:
A licensing error occurred while the client ...
- 905
0
votes
1
answer
3k
views
Reassembly fails at destination
Say I have Host1 & 2 connected to a router with different speeds.
Host1 <--100 Mbps--> Router <--10 Mbps--> Host2
Host1 sends 10MB of UDP data using nc command to Host2, but the ...
- 101
0
votes
1
answer
5k
views
Where IP fragments are reassembled into one fragment? [closed]
Reading about IP fragments found controversy between various teaching materials.
In book:
"Fragments need to be reassembled before they reach the transport layer at the destination."
"The ...
anon
0
votes
1
answer
22k
views
Forcing IP fragmentation and reassembly for some traffic thru a VPN tunnel
Is there a way to force IP packet fragmentation before they go into tun0 and then force reassemble them on the other side of tun device?
I have some IPSec traffic that I can not control, and it wants ...
- 265
2
votes
1
answer
1k
views
VPN problems: MTU and Don't-Fragment
I am setting up a VPN on Ubuntu 14.04LTS which uses IPSEC and performs NAT for clients. It is basically working - I can connect to it from a clinet (Android device) and browse (for example) www....
- 181
0
votes
1
answer
1k
views
Fragmented DNS Packet
The DNS response against my domain is 1228 bytes long and I need the packet to get fragmented in 3 packets. To achieve this I have set the MTU at name server (bind9 running on the machine) to be 500. ...
3
votes
0
answers
3k
views
Does netfilter reassemble IP fragments when packet is forwarded?
IP datagram should be reassemble in the termination of the path because the fragments may arrive from different paths. I think Netfilter need to reassemble a IP datagram to inspect the whole payload ...
- 203
22
votes
3
answers
32k
views
OpenVPN: How to mitigate path MTU issues on a per-client basis?
We have dozens of embedded devices installed at customers, all calling home to our OpenVPN service. That works fine in general, but a few of our customers have severe path MTU issues. Our influence on ...
- 3,412
0
votes
1
answer
574
views
Can a source send two fragmented IP packets at the same time?
I'm developing an app that does NAT between a virtual TAP interface and a physical interface, and I'm not sure how much buffer should I allocate for IP fragmentation.
According to Wikipedia the ...
- 270
15
votes
1
answer
26k
views
Why is the "don't fragment" flag set in https and ssh protocols?
I've found a lot of information specifying that this is the case, however, I am really looking for the reason behind this. Why is it necessary? Is it necessary?
- 253
10
votes
1
answer
10k
views
Why is iptables rejecting the second and subsequent fragments of an allowed packet?
I have two hosts which are attempting to set up an IPSec connection with each other. For this they have to communicate on UDP ports 500 and 4500, so I opened them in the firewalls on both ends (shown ...
- 246k
3
votes
1
answer
2k
views
Does Windows XP automatically reassemble UDP fragments?
I've got a Windows application that receives and processes XML messages transmitted via UDP. The application collects the data using Windows "raw" sockets, so the entire layer 3 packet is visible.
...
- 133
4
votes
2
answers
767
views
Matching last fragment of IP packets using tc or ipfilter
I am transmitting UDP packets of say 2900 bytes. Due to fragmentation, packet is divided in 2 IP fragments. My tc u32 filter (more fragments bit and IP/PORT combination) matches only first fragment ...
- 41
3
votes
1
answer
100
views
IP segmentation occouring at irregular boundaries
I have an IP packet of header length of 20 Bytes and data length of 4096 Bytes. The maximum transfer unit of the network is only 1500 Bytes. As I understand fragmentation, the fragmented packet will ...
- 303
3
votes
2
answers
219
views
seeing remote MTUs of 250 and 68. is this ever valid?
I'm seeing an ICMP storm from a mobile phone netblocks belonging to "TELEFONICA MOVILES". Periodically we will get upwards of 5 million in a few seconds, all something like this:
08:12:05.740781 IP (...
- 208
1
vote
3
answers
2k
views
Implementing IP fragmentation
I'm working on an application that does network traffic generation. The application has eth1 in promiscous mode. So it directly handles all incoming and outgoing traffic.
One of the features I'm ...
- 1,155