Questions tagged [mtu]
"Maximum Transmission Unit" (MTU) is the maximum number of bytes a frame or packet may have on a network (in several layers of the OSI model). Wrong MTU can lead to packet loss.
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Does changing MTU need restarting the application?
Let us say we have an aerospike cluster running with interface mtu as 1500. If I want to switch to jumbo frames, do I need to restart the aerospike cluster? If yes, why?
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hetzner private network, 1 docker host, 1 pfsense, I keep getting "TCP Previous segment not captured" from my containers
this is the network design
https://imagebin.ca/v/5NNDpuDwq9PT
it's hosted on hetzner, 1 firewall with a public facing interface, pfsense.
1 docker host with two interfaces, one connected to the ...
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MTU 9000 and 1500 when machines with MTU 1500 send data to machines with MTU 9000
we have some machines in the cluster
linux machines as Linux_a , linux_b are configured with MTU 1500
while linux machines - linux_1 and linux_2 are configured with MTU 9000
so
linux machines - ...
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VirtualBox adapter MTU settings over 1500
I create an adapter for Oracle VirtualBox (as a host-only). It runs perfectly; but I need to change MTU size to 1600. When I come back to host-PC and I opened terminal. Then I got these results.
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VLANs with mixed MTUs trunked over a LAG
I'm contemplating enabling Jumbo frames for a specific network/VLAN (a dedicated storage network). Ports are spread across two switches, linked together using a LAG, which is configured to carry all ...
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Linux route cache seems to load outdated settings
On SLES 11 SP3 (Kernel 3.0.101-0.46) I see the following route behavior:
When I set a route specific MTU once via ip route change ... mtu lock 1500, everything works as expected (setting an MTU of ...
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Can't mount read-write iSCSI with MTU=9000
I'm attempting to connect my desktop (running debian 7) to a QNAP NAS (running QTS 4.1.1) using iSCSI with an MTU=9000. The network infrastructure consists of a cat5e crossover cable between the ...
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Debian don't forward through L2TPv3 more than mtu l2tp virtual interface
R3--R1--Internet--R90
R3: ip addr 10.123.0.3
R1:
sudo ip l2tp add tunnel tunnel_id 699 peer_tunnel_id 699 encap udp local 5.254.174.8
remote 5.254.174.90 udp_sport 699 udp_dport 699
sudo ip l2tp add ...
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How do I force a specific MTU for only certain TCP ports?
Background
I have a set of embedded hardware deployed in the field. These remote machines connect back to my servers at AWS running Ubuntu and I use the iptables mangle chain to lower the MTU to 500 ...
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Configure LeftHand iSCSI SAN for jumbo frames after clients are configured
This is similar to enabling jumbo frames on an iSCSI network after the fact but in our case we configured the switches and then went through all the hosts, enabling jumbo frames (we may have screwed ...
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System MTU for SAN switch
I have a SAN with redundant cisco 2960s when I set it up a while ago I set all of the interfaces to use an MTU of 9000. I was looking at the config today and I noticed this line system mtu routing ...
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What is the right way to temporarily disable/enable PMTU Discovery on a Linux box?
I've a few pcaps that contain packets larger than standard ethernet MTU size of 1500B. I searched about this and found refs pointing towards Jumbo Frames. I now understand that since I'm on a GBE ...
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How to setup linux to retransmit TCP packets by reducing the packet size like OS X
On OS X I noticed that for packets which are not ACKed, the system retransmits them with reduced packet size. This can be seen in the image below.
Is it possible to enable the same behavior in Linux ...
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Why does setting MTU 1452 solve Internet problems and how to fix root cause?
In our church we get Internet uplink from a friendly neighbor’s WiFi. At first everything seemed (at least) fine but since some weeks general “Internet stability problems” increased and since approx. ...
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Ping : How to differentiate between Host powered off and MTU too long?
I changed the eth0 MTU size to 1550(using : ifconfig eth0 mtu 1550) and ran ping -c 1 -M do -s 1500 -w 5 {some other IP} and
The output I see is,
--- x.x.x.x ping statistics --- 5 packets ...
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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 ...
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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 ...
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Force Windows to send packets as soon as they arrive the nic
I have a network application running on Windows Server 2008 R2, that must send small packets in a very short time interval, each microsecond matters. My problem is that windows accumulates the packets ...
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MTU between Juniper and Cisco, cause of packet loss?
This office has a network consisting of Cisco Catalyst and Juniper EX L3 switch. Cisco Router and Juniper L3 switch share a OSPF area in between them.
Hosts on Juniper side are running FTP servers ...
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Computer Networks bonus: find MTU less than 1500 [closed]
This is a bonus question in my Networks class: I have to find a destination for which the path MTU < 1500 bytes.
For example using the command
traceroute -F www.uwaterloo.ca 1500 works, and ...
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Jumbo MTU and switches
I have a network with several file servers, workstations and application servers. For simplicity we can consider it all attached to a single switch, say Dell 4032F with maximum Jumbo MTU size of 9216. ...
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Cannot transfer data from one specific system (MTU issue?)
Summary
The default MTU value prevents data transfer for one system. Reducing it manually enables the data transfer once more, but this manual adjustment is unnecessary on an adjacent system.
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How is the Ethernet payload only max 1500, while I can ping with larger size packet?
Just recently I came to know that the payload of Ethernet is max 1500 bytes (mtu).
The first thing that came to my mind was that we can ping with much more size than that. So I thought maybe the ...
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Cisco 2960X and Jumbo frames on particular ports
I would like to setup several ports to be able handle jumbo frames.
This will be only for my backup nas connected to ESXi host.
I did create vlan 103 where I changed mtu size to 9000.
Problem is when ...
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IPsec transport mode and MTU
[Similar to Right way to set the MTU of an IPsec Client (Linux/Racoon), but different in that there is no router on the responder side]
I have a setup where machines in a local network need to talk ...
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Jumbo Frame configuration & VMware
I am hoping one of you can help clear up some of my confusion on this matter.
We have 2 new catalyst 3750 switches to support our VM hosts and SAN arrays. The SAN arrays utilize jumbo frames with an ...
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openvpn TCP/UDP slow SSH/SMB performance
I have question about strange behavior of my openVPN configuration on Debian lenny. I have 2 server configs (one proto tcp-server based and one proto udp based). ISP bandwidth is 7Mbit/7Mbit.
When I ...
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Under FreeBSD, can a VLAN interface have a smaller MTU than the primary interface?
I have a system with two physical interfaces, combined into a LACP
aggregation group. That LACP channel has two VLANs, one untagged (the
"native vlan") and one using VLAN tagging. This gives us:
...
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What should be the MTU Size for Windows Servers on the same Network
I have two windows servers on the same network, communicating to each other. What would be the best way to come up with the MTU setting?
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New network not using updated TLS and failing to connect to certain websites
I have 2 networks that are configured just about identically. The both have the same Router - Mikrotik RB2011UiAS-RM, with a direct fiber link to the ISP. I am using the same ISP for both networks. ...
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MTU resetting back to 1500 after `netplan apply`
I'm trying to change the MTU of the eth0 interface on my machine running Ubuntu 18.04 (Nvidia Jetson Xavier NX). Running sudo netplan apply successfully sets the mtu for eth0 to 1280.
Unfortunately, ...
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strongSwan VPN tunnel (IKEv2) established but traffic times out
I have a VPN server that tunnels traffic to a PostgreSQL database server which is otherwise unreachable from the internet. The VPN is only reachable by IPv4.
Problem
All clients can establish a VPN ...
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How to change cisco 3750 specific port MTU to 9000?
How to change cisco 3750 specific port MTU to 9000? I do not want to set it as a system global command for all ports.
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how to safely increase a network's MTU
I want to increase the Ethernet Maximum Transmission Unit (MTU) for some hosts on a local network. Is there a known sequence of steps to follow? Or, can I just tweak each host's MTU as needed and it ...
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Path MTU is not always 9000, only in one direction
I have a question about MTU or path MTU. In my setup I have 2 computers (firewall, Windows PC) and one NAS, each with a gigabit interface. They are connected throughout the same gigabit switch. In all ...
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Force jumbo packet fragmentation
We are in a cluster environment. We have compute nodes with jumbo packets enabled and a MTU of 9000. We are running into some issues in tracebacks to an address outside of our lan, where jumbo packets ...
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dose setting Jumbo frame on linux redhat influencing OS performance?
We set the MTU to 9000 on all our linux machines ( we have redhat machines version - 7.3 ) , linux machines are part of hadoop clusters
we want to know if set the MTU to 9000 can be negative on OS ...
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linux fine tuning after setting the MTU to jumbo frame
We want to set the MTU to 9000 bytes on our Linux machines (distribution is Redhat 7)
In this case, how would I tune the memory page size according to MTU size of 9000 bytes?
Also, what are the ...
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MTU issue - Packet loss with certain Destination
A customer is having issue with our system and after investigating and analyzing tcp traffic with tcpdump, I noticed that fragmented packets were not received by our cloud server (OVH).
I did some ...
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Centos 7 pptpd mtu size
i'm using pptpd on centos7 as PPTP VPN Server
how can I change the MTU size on server side cause some users cannot connect to the server
thanks
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HTTP webserver gateway timeout 504 only from one ISP
I have configured a nginx http webserver to serve a site on CentOS 6 Virtual machine. every things are works fine but when I connect to site from a special ISP, the site wait and after a while respond ...
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Server Not Working With Jumbo MTUs
I am a network engineer & my server guy doesn't appear to be able to get the jumbo MTU's to work on his NIC team. We are using LACP for two 10gig interfaces between the switch. I am 100% certain ...
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Change Xenserver 6.5 MTU
How do I go about change the MTU setting for my management interface in xenserver 6.5? Right now its set to the default 1500 but I want to increase it to 9000.
For my setup I have 2 nics on each host ...
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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. ...
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Severe performance issues sharing openvpn client connection to LAN clients virtualbox
I am trying to set up an internal network in Virtualbox in order to share an openvpn client tunnel with multiple VMs acting as clients that should be completely isolated from everything except for the ...
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Finding network type using MTU
For example MTU of Ethernet is 1500.
Now if the packets are fragmented, then observed MTU will be the MTU of the router (i.e. less than 1500).
Is there any method to find out the type of the client ...
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Setting the MTU of a virtual Switch on a qNAP NAS (QTSHero OS)
For a project that I am currently working for, I bought a QNAP NAS (TVS-h1288X). In that project, I have multiple network cameras. On the NAS, I have a Windows 10 VM which is supposed to store all the ...
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windows update error 80072ee2 caused by linux router, possible mtu issue? [closed]
For a few days now, the Windows 7 workstations on my network have been unable to connect to Windows Update. They are getting the infamous error 80072ee2. They are connected to a simple SOHO switch. ...
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centos 5.6, virtual on Vsphere
suddenly my virtual centos server (5.6 on VMWare-VSphere) is not working...
It started with the url not responding, nor the ip. (NO HTTP response, no ping).
When I entered on the server via ssh to ...
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I can not decrease MTU on my nic
I'm trying to decrease the MTU value on my machine but I receive this response:
[root@apache1bpreprod acn]# ifconfig eth0 mtu 1350
SIOCSIFMTU: Invalid argument
Why? i expect problems to increase not ...