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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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different MTU sizes for bond aliases

I have a bond interface but I want to change the MTU to 1500 only for bond9:22 Is this possible? bond9:22 Link encap:Ethernet HWaddr 00:0E:0C:E4:BE:F9 inet addr:10.7.18.58 Bcast:10.7.18.255 Mask:255.255.255.0 UP BROADCAST…
cateof
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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 1500 will that cause any problems? or because this…
Peter
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MTU issue with one site only

I am currently troubleshooting an issue where some users on Windows 7 and XP systems cannot access an SSL website on our network. The same site works fine on our servers (Server 2003, completely up-to-date, and a Ubuntu Server box) and all of our…
Matthew Iselin
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Maximum Transmission Unit of VDSL

A simple question (hopefully) but with no clear answers when doing a Google Search. What is the MTU of VDSL (not VDSL2)? With ADSL it was 1492, but most ISPs added PPPoE/PPPoA headers reducing it to 1452, is this still the same when it comes to…
Metalshark
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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 EC2 always have the "Don't fragment" flag…
basin
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Increasing MTU size

Why would increasing the VLAN MTU size cause things to break? We have a customer who wants 2000 byte packets for some reason, so I increased all the physical links to 9216, which didn't cause any problems, but it didn't actually allow the 2000 byte…
abatie
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How to setup permanent MTU size in RHEL 7 for eth0 interface?

I am using RHEL 7 and trying to setup permanent MTU size to 8500. Not able to find a way to set it up permanently. The server does not have dhcp.conf file in it. I am using below command for temporary solution. But the MTU size gets reset after…
error2007s
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NFS insists to send packets over MTU, nftables might be the solution

I have an NFS mount over a Strongswan IPSec tunnel, which is encapsulated in a 6to4 tunnel. The IPSec is because I need encryption for NFS traffic, the 6to4 is because the VPS provider won't assign a native IPv6 prefix to my server. Because I had…
MegaBrutal
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Different length between ping and tcpdump

I do not why I am not able to see under tcpdump the correct length value which should be $((9706-28)) = 9678, but I see 9686. On both side there is a MTU set to 9706 which maximum value for the interface which I am using. I run command: ping -D -s…
sqr
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Requirements to achieve Jumbo Frame (mtu = 9000) with PXE Enabled networks

What I should be looking for when trying to enable Jumbo Frames in networks that relies on PXE for server booting? As far as I know I must have: Network switch capable of MTU >= 9000 The ability to enable Jumbo Frames not only on the network…
Vinícius Ferrão
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Can't reach server probably caused by openvpn mtu

What I try to achieve: Reach the server on LAN via OpenVPN Symptoms: SSH connection hangs on SSH2_MSG_KEXINIT ssh -vvv emmy@10.0.0.101 OpenSSH_8.2p1 Ubuntu-4ubuntu0.2, OpenSSL 1.1.1f 31 Mar 2020 debug1: Reading configuration data…
Benedikt Lang
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SSH pauses - perhaps MTU/packet size too large - how to confirm and possibly resolve?

I have a MacOS client and Linux server (non-root access). I'm using 2 versions of a tool for remote desktop control. Version 2 worked pretty well - some small bugs. The vendor has updated to version 3. Version 3 fixes many bugs but has one major bug…
nachum
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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?
Tarun Dev
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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 private network and one facing the internet, the public…
dada216
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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 will "just work"? One condition is only some…
JamesThomasMoon
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