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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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Telecom provider not supporting MTU higher than 1515 for leased line

We have ordered a 100 Mbps leased line and did not specify our requirement to have a minimum of 1530 MTU supported. The telco now sent us a feedback that they do not support 1530, but only 1515. Did anyone experience something similar? And what can…
Paul Moe
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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 - linux_a and linux_b send heavy data to linux_1 and…
shalom
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can we mix MTU values in cluster

we have hadoop cluster ( all machines are linux redhat machines version 7.x ) on the VM machines we set MTU=8900 and all other machines we set MTU=9000 we set on VM MTU=8900 because we saw some network problems with MTU=9000 My question: dose mix…
shalom
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Problems with TCP retransmission, duplicates etc. on CentOS Linux

I'm running Vyattagateway with a CentOS Linux behind, and IPSec tunnel in front. Trying to display my setup: PARTNER-NETWORK <--- IPSec (GRE, MTU 1420) ---> VYATTA (TUNNEL, MTU 1420 <> eth0, MTU 1500) <---> CentOS (eth0, MTU 1500) <---> internet…
Alfred Balle
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how to know if my servers should use huge pages ( memory page size )

we have several servers in cluster , and we want to know what in general in which cases we need to configure huge pages ? I have also few quastions dose "memory page size" is equal to Huge pages ? in my linux server I entered the following command…
shalom
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Random connection resets between browser and Linux server - MTU wrong or ICMP not getting through?

I've been seeing random ERR_CONNECTION_RESET errors in my browser (Chrome, Firefox or Edge running on different machines, Windows 10 1709) when I try to edit web pages on a remote Linux server running Ubuntu 16.04 LAMP. It's very hard to pinpoint…
Phil McKerracher
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VLAN MTU on Linux with Intel Pro/1000 PT Server Adapter

For some reason MTU still seem to be an occasional issue with trunked connections. In this case I have a trunk connected to an Enterprise Linux 5 server. I use standard vlan seperation in Linux, and have the vlan interface bridged with virtual…
Roy
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ping fails with MTU >= 298

For context, my original problem is that my ssh connection to my servers hangs at expecting SSH2_MSG_KEX_ECDH_REPLY when i connect to them via VPN (in this case, an OpenVPN running in pfsense). The Internet indicates that may be linked to MTU…
iCart
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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. ifconfig : ..... vboxnet0 Link encap:Ethernet HWaddr…
user428688
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Is there a utility or way to get the PMTU/MTU of a remote system quickly?

Is there a utility or linux built in to get the PMTU/MTU of a remote system quickly (sub 1 second preferably)? If so what is it and what syntax does it require? Google searches have not been my friend today and the only solution I've found is a full…
Bravo Delta
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Jumbo frames (mtu 9000) on Debian 7.10 servers with BCM57800 NIC (bnx2x)

I'm working on 2 servers under Debian 7.10 with Broadcom Corporation NetXtreme BCM57800 1/10 Gigabit ethernet. I have done the following for both servers: ethtool -g eth0 Ring parameters for eth0: Pre-set maximums: RX: 4078 RX Mini:…
Eliot B.
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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 relevant VLANs (trunking). I presume the…
sxc731
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Linux MTU and UDP

Can someone please explain this behavior to me? I have a few VMS (centos) running on a cloud provider. The interface is set to the standard 1500 MTU. pinging with large ICMP packets works fine: # ping -s 1600 10.132.6.3 PING 10.132.6.3…
Dave0
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Weird network interaction between Vista and Ubuntu

I have a network where my WAN (a CableModem) goes into a (dubiously configured) Ubuntu box which acts as the router for the whole company. We recently switched our ISP, and we're getting a very weird behavior. In Vista/Server 2008 machines, some…
Daniel Magliola
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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.google.com. However I cannot browse www.bbc.co.uk. …
Mark Smith
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