ESXi MTU sizes?

Similar Questions

• How to choose right for the WAN Interface MTU size?

  Hello

  I would like to know How to determine the right size MTU to set in the properties of the WAN interface (in my case, NSA appliances).

  First of all. I noticed that with SonicOS Enhanced 5.9.x, there is a Tool of diagnosis called PMTU discovery:

  

  This tool is not available with SonicOS Enhanced 5.8.x.

  I guess using this built-in tool is a way to determine the right MTU size to apply.

  Second, for SonicOS versions that do not have this tool and to understand just how to manually determine the size MTU, I would like to know what is the method to follow.

  On the Internet, I found this method by using the ping-f-l command. Once you have determined the largest possible packet size, it ask you to Add 28 to that number and you get the MTU size to define the interface.

  Case study:

  In my business, there are 2 sites: 1 in China and 1 in South Korea. Both have a firewall SonicWALL NSA.

  To determine the MTU size that is applicable from the Chinese site, I get the same results with the 2 methods mentioned above.

  With the help of the PMTU discovery:

  I get 2 IPs: 8.8.8.8 and the Korean FW IP WAN. I get the same result: 1500.

  

  

  However, I noticed that the MTU size should be set to its maximum (1500) of size on the properties of the interface WAN for this test to work properly. Indeed, when I put in 1404 to test, PMTU discovery find 1404 such as MTU size:

  

  

  With the help of ping - f - l:

  When you use the ping with FW Korea WAN IP method, I found 1472 as the maximum packet size:

  

  According to the method I've read on the Internet, adding 28 will make me a MTU of 1500, same size as the PMTU discovery method.

  My question is: can you confirm that these 2 methods are correct determine the MTU size to set the WAN interface? Especially the one with the ping command? If not, how do?

  Thanks in advance for your comments.

  I can tell you that as technicians, we use the way to CMD line to adjust the MTU on WAN interfaces. We saw this as a number to work with.

  Thank you
  Ben D
  #Iwork4Dell

• VM - fex mtu size

  Hello

  I need to set up mtu 9000 on dynamic vNIC (vm - fex vNIC).
  But I have found no guide on how to do it. I followed the guide of config vm - fex for KVM, but in the strategy of dynamic connection vnic I've not found any parameter to change the mtu size. By default all NICs for Dynamics become mtu 1500.
  Someone has documents or advice on how to set the mtu value dynamic vNIC 9000 (vm - fex)?

  Sent by Cisco Support technique iPad App

  Hi, Alois,.

  The MTU size can be changed at the interface of VM - FEX using a QoS policy in the port-profile.

  Here's how to change the MTU size when using Vvm - fex:

  (1) create a QoS policy on the LAN tab,

  (2) all by selecting a priority, choose the system QoS class that has an updated MTU size the configured.

  (3) create a profile port to be used by a NETWORK adapter to virtual machines (which, in turn, will get it one of the dynamic interfaces)

  (4) in the port-profile specify this QoS policy

  I hope this helps!

  . / Afonso

• Test on IPSEC Tunnel MTU size

  How can I test the MTU size, through an IPSEC tunnel to an ASA 5520 to an ASA 5510? I have fears that problems with my equipment are due to the insufficient MTU size.

  You can use extended ping to see the size of the package you can send through the tunnel with little DF

  game do not fragment. for ex: -.

  If you have two windows machines, one on each side of the vpn with ip add 10.2.2.10 and 10.3.3.10.

  Ping 10.2.2.10 to help: -.

  Ping 10.3.3.10

  success of the response

  Ping 10.3.3.10-l 1500 f {where-l 1500 sets the MTU to 1500 and f said do not fragment}

  package has need to be fragmented but df set

  package has need to be fragmented but df set

  Ping 10.3.3.10-l 1300 f

  the fragmentation of packets needs but df set

  Ping 10.3.3.10 l - 1270 f

  success of the response

  success of the response

  Thank you

  Manish

• Jumbo frames, change the MTU size without VM guest tension

  I'm trying to disable jumbo frames, specifically to change the size of the mtu to 1500 (instead of 9000) in vcenter on some hosts. Some hosts run esxi 4.1, others are running esxi 5.0. I wonder if it is absolutely necessary to turn off the virtual machines that are connected to the iscsi san network while making this change, or is it relatively safe to make this change, while VMS are running.

  Each VM has active multipathing, 2 vswitches with 1 NIC associated with each.

  I know how to make the changes, regarding my questions whether it is possible to safely make changes while VMS still access the SAN.

  Yes, it is something that I do in my lab quite frequently without using maintenance mode. Memaad notes, maintenance mode is always preferable to avoid unnecessary risks, but it's finally to you.

  See you soon.

• ESXi memory size error

  Hello

  I want to install ESXi on a Dell Optiplex 755 which has 2 GB of RAM. (I'll buy later), but the installer says: ERROR you have 1.96 GB 1.97 GB of memory is necessary.

  I have try to disable my VGA card and everything in the bios.

  and

  I try to add the line minmemorycheck = "False" (http://www.yellow-bricks.com/2009/05/08/running-vsphere-within-workstation-will-take-up-a-lot-of-memory/)

  I have no idea what to do I orderred some already of memory (2 GB), but I have to wait 10 days until they sent because the suplyer is slow...

  I hope someone can help!

  I'm afraid that the only reliable solution is to add memory. You might have seen in other discussions, some users have been able to install ESXi after a BIOS update for example,..., but with only 2 GB of RAM - even if you are able to install ESXi - you can't do a lot (such as the installation of VMS).

  André

• Change the MTU size to vmkernels on dvSwitch

  Hi all

  I have about 40 ESX hosts that belong to dvswitches different 6 and 6 different groups. Each host has 6 vmknics created for the dvswitch and all have value mtu of 1500. Can someone help me with a cli script to change all vmks 9000 MTU?

  Please let me know if additional information is required

  Thanks in advance.

  Try it like this.

  $MtuSize = 9000
  foreach($dvSw in (Get-VirtualSwitch -Distributed -Datacenter MyDC)){
    $dvSw.ExtensionData.Config.Host | %{
      $esx = Get-View $_.Config.Host    foreach($pnic in $_.Config.Backing.PnicSpec){
        $netSys = Get-View $esx.configManager.networkSystem      foreach($vnic in $netSys.NetworkConfig.Vnic | where {$_.Spec.DistributedVirtualPort}){
          $spec = [VMware.Vim.HostVirtualNicSpec]$vnic.spec        $spec.mtu = $MTUSize        $netSys.UpdateVirtualNic($vnic.Device,$spec)
        }
      }
    }
  }
  

  It will update the MTU value of each vnic connected to a dvSwitch

• ESXi 5 dvswitch and MTU settings

  Edit: I'll post the config info here for anyone else looking for a quick "How To".  It's super simple but not obvious.

  After you add a host to the DVSwitch, navigate to Configuration, Networking, vSphere Distributed Switch, manage virtual cards.

  Here you can add virtual NICs that you can set the MTU value for each of your groups of port.  Hope this helps someone else.

  I have a question about MTU settings.

  In my scenerio I only have 1 2 port 10gig card at my host.  I have every port as a dvuplink to separate switches.

  My question is, when you set the MAX 9000 MTU to support frames for ISCSI dvPortGroups, do all your other traffic in VM network exchanges 9000 thus, change d ' assign my stand alone equipment is 10/100/1000 MTU 1500.

  so I guess what I'm wondering really is,

  a guest virtual OS/machine running on this dvswitch in a dvportgroup, MTU is always maybe 1500? While he could talk to hold single device on the fabric.

  I know to support ISCSI frames and must be supported from BEGINNING to END, mine is esxi to switch to the san.

  so I just need a dvswitch dedicated for MTU 9000 and a dvswitch dedicated for MTU 1500 or 1500 traffic cannot exist in the 9000 switch?

  I'm relatively new to the frames, so I will try to figure out how my design "should" be.

  I do not have the budget to add more 10gig network adapters on each host.  I know that sounds bad but that is where we are. It would be just a waste of flow... I just don't need that much flow.  2 uplinks of 10gig already more than meet are needs.

  I have attached a presentation of how visio I wanted to put this out, but once I started to think through MTU, I was like uh... which will not work, it will be?

  Samples of Robert wrote:

  My question is, when you set the MAX 9000 MTU to support frames for ISCSI dvPortGroups, do all your other traffic in VM network exchanges 9000 thus, change d ' assign my stand alone equipment is 10/100/1000 MTU 1500.

  so I guess what I'm wondering really is,

  a guest virtual OS/machine running on this dvswitch in a dvportgroup, MTU is always maybe 1500? While he could talk to hold single device on the fabric.

  Allowing a large MTU on the dvswitch will not do damage to your virtual machines. It is easy to get confused about this, but the MTU setting on the switch, it's just that it will allow the biggest executives to 1518 bytes. The MTU size changed the switch will be invisible to your virtual machines and they will continue to use default MTU 1500 without problems.

  In other words, you can have with 9000 VMkernel iSCSI adapters and virtual machines with 1500 on the same dvswitch.

• Fix the size of the MTU for the E4200 using DSL?

  I wanted to check the MTU size manual correct setting for the E4200 using DSL.  An indifferent Linksys Tech told me that the correct MTU size should be manual to 1375. I am running firmware v1.0.01 basically, I have a Mac connected to the E4200 and 2 wireless computers.  I would like to get the best speed of the Internet I can, wire and wireless.  What do you suggest me? Thank you.

  See here

• ESXi hosts SBS 2011, clients lose network via VPN

  Greetings,

  We have an ESXi Server (in a lab environment) who perform a SBS 2011 and a Windows 2003 (Terminal Server).

  We have two locations, connected via a VPN IPSec (2 boxes of ClearOS).

  The ESXi host is located in building r. customers in the construction of an experience no problem at all.

  Customers in the building B often lose connectivity to network share. We also failed when copying data. Do not forget that the servers are located in the building and issues affecting only users in the B building.

  We noticed the event ID 2012 on the VM SBS 2011 event viewer.

  The two buildings are connected to a cable broadband 10 mb / 1 mb ISP.

  NOD32 Antivirus is installed on the two virtual machines

  Any help would be appreciated!

  Thank you

  Fred9777

  Hello

  There are a few things to look out for more such links. The following steps were made on W2K and W2K3, so that they are still applicable for you.

  (1) is the VPN capable to manage the packet being sent by site B MTU size, sometimes the MTU on VPN size must be less than the default value of 1500 set LAN. You can check this scathing your server with a command like

  ping f-l 1500

  If you get a message like "packet needs to be fragmented but DF parameter.

  You will need to reduce the size of the MTU TCP/IP in the client registry. Try to ping the server with a size of 500 bytes and see how it goes.

  (2) setting the server TCP/IP stack

  In the registry HKLM \SYSTEM\CurrentControlSet\Services\Tcpip\Parameters, create or modify value DWORD of TcpMaxDataRetransmissions. By default, it is set to 5, but I recommend double this value to 10. The TcpMaxDataRetransmissions value is the number of retransmissions of TCP of a data segment without acknowledgement of receipt on an existing connection. TCP retransmits data segments until they are acknowledged or until the expiry of this value. Basically, when a client does not meet a package from the server, the server will attempt to retransmit the packet until TcpMaxDataRetransmissions many times. By increasing this value, you give the customer more time to answer on the server, which will help improve the flaky connections or connections with latency or higher than normal packet loss.

  HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\KeepAliveInterval and HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\KeepAliveTime.

  Both entered DWORD.
  KeepAliveInterval determines the interval between retransmissions keep until a response is received. If a response is received, the delay until the next keep alive transmission is again controlled by the value of KeepAliveTime.
  The connection will be broken once the number of retransmissions specified by TcpMaxDataRetransmissions is remained. KeepAliveInterval is set by default at 1000, which is one second.
  KeepAliveTime controls how many times TCP attempts to verify that an idle connection is still intact by sending a living package of the Dungeon. If the remote system is still reachable and running, he will acknowledge receipt of the living transmission to keep. KeepAliveTime is set by default to 7 200 000, or 2 hours.

  I hope this helps.

• Setting MTU on Linksys SRW2024

  How do you define the MTU size on the Linksys SRW2024 concert switch?

  Thank you!

  The MTU size is necessary to allow the passage of executives more than 1500. I found the necessary setting on the Admin page to enable frames. In order to be a layer 2 switch, this isn't the answer. You must enable frames more than 1500 to allow their passage.

• Trouble with my MTU settings

  I use a WRT54G for online for a xbox360 and computer connectivity. Three days ago my power went out, he came back the same day. Since then, whenever I try to play online with my Xbox 360 it says "MTU test failed" and says my MTU settings are too low.

  I tried several ways to solve this problem and none have worked up so I thought I would try here also. I'm always looking for other ways to fix it but if anyone has any useful advice, please report it.

  BTW my 360 and the computer are connected to my router, which is connected to my modem is an Arris cable modem.

  Follow this, it will surely work...

  Open an Internet Explorer browser page. In the address bar type - 192.168.1.1
  Leave the name blank user & admin password usage, it will open your router configuration page...

  Then click on the tab "Games and Applications" and click void
  tab "Port Range forwarding"
  (1) on the first line in the box, type Application in "Xbox", start box
  type in 88, in the end box, type 88, in the Protocol keep both in ip
  type in address 192.168.1.20 and give a check mark on the enable box. Click on save settings.

  (2) on the second line in the Application in "Xbox Live" box type in run box
  type in 3074, in type of box in 3074, Protocol keep both in ip
  type in address 192.168.1.20 and give a check mark on the enable box. Click on save settings.

  Once you return to the page setup, click the status tab. Take a note of DNS1 and DNS2.

  Click Setup... Change the MTU to manual and change the MTU size to 1452... Click Save

  Parameters.

  Now to assign the ip address given on your xbox
  IP address :-192.168.1.20
  :-255.255.255.0 subnet mask
  default gateway:-192.168.1.1

  To set the static IP address on the X - Box go to the network settings on the X - Box... Also assign the dns

  address on the xbox in the same way...

  Turn off your router and the X - Box... Wait a minute... Turn on the router first... Wait a

  minute... Test your X - Box... It needs to connect...

• HOW TO ADJUST SETTINGS MTU FOR VISTA?

  HOW TO CHANGE THE MTU SETTINGS?

  Hello

  You use a command prompt

  Start - type in the search-> CMD box find top - make a RIGHT CLIC on - RUN AS ADMIN

  Change the MTU in Windows Vista
  http://www.Kitz.co.UK/ADSL/vistaMTU.htm

  How to set manually the size MTU in Windows XP 2003 2000 Vista
  http://www.windowsreference.com/Windows-XP/how-to-manually-set-the-MTU-size-in-Windows-XP-2003-2000-Vista/

  ------------------------------------------------------

  A good program that can help the MTU value and other parameters.

  Try this - download - SAVE - TweakMaster Pro - go to where you put it - right click on -RUN AS ADMIN

  TweakMaster Pro - 30 days eval
  http://www.TweakMASTER.com/register.php

  Run it - MTU change advanced optimization settings - network adapters - for everything you need.

  I hope this helps.

  Rob Brown - MS MVP - Windows Desktop Experience: Bike - Mark Twain said it right.

• MTU on line ADSL via VPN

  Hi, I use PIX501s with os6.3 (3). They are connected to the internet via ADSL (pppoe). Firewalls are deployed in the Center and network spoke in the Center which is a VPN 7140 router. There are among the sites of links from site to site VPN. There are all Windows domain controllers that need to replicate with the central domain controller in local LANs. It seems that all the rays can ping the host server and vica versa but replication and the remote desktop connection does not work. The access provider ADSL told us to use 1454bytes as MTU on the external interfaces. If I put all the MTU on the PIX and the Central 7140 to 1100 (which should be small enough for ADSL) it does not help. But if I set the MTU size on the central domain controller Windows Server (whith that must replicate all servers spoke and who must be reached via desktop remotely), everything works fine, but this is not a nice.

  How can I know the PIX or the VPN router to connect the correct MTU settings for Windows servers? Or how can I adjust the MTU on the CISCO devices that work?

  The configs are attached

  What OS and what level of service pack is currently running on your domain controllers?

  If it is win 2000 Service Pack 2 from this link:

  http://support.Microsoft.com/default.aspx?scid=kb;en-us;301337

  indicates that the server will ignore requests to lower the mtu when the request comes from a server (or gateway) on the same subnet as the host windows. SP3 resolves this problem.

  I'll do some more research on the Microsoft site and see what I come up with. It seems that your problem might be this or something similar. However, the dc hub seems to be controlling the mtu size, so even if a remote client establishes a replication, the hub dc want to use its mtu and not that of the client, which should be lower as the pix should see the negotiation of mss of tcp and lower according to the interface mtu.

  I'll post what I find.

• VPN and MTU issues

  Recently, I have set up a 1721 running IOS c1700-k9o3sy7 - mz.122 - 15.T5.bin

  This router terminated a VPN with another router, a 1721 with the exact same version of IOS. This router has initially been connected via a WAN link on eth0 wireless. We moved their on a t1 as the main interface with the wireless as a backup. Then we had to

  -Configure a loopback - its ip address device would end the vpn

  -make the source of the vpn packages come from the loop

  -Configure static routes w / higher administrative distance

  Do all this we tested VPN - they worked. Unplugged at t1 connection and traffic moves on the wireless. We checked the vpn clients could connect. Everything worked ok...

  Except when you move large files between hosts behind fa0 via the vpn to the guests at the bottom. To prove the vpn worked and routing was in place, we could telnet from a host behind fa0 via the vpn to a remote host and you connect... Then, we would try an ftp files more. We could connect to the ftp server BUT once a file transfer started things would hang.

  We opened a Cisco tac case and it turned out that the addition of

  IP tcp adjust-mss 1300

  the interface fa0 fixed all - file transfer worked.

  My question why would be reduced aid package size? The vpn add some packages generals cauing more large packages to remove?

  A clue was here, BUT it's PPPoE - no VPN...

  http://www.Cisco.com/univercd/CC/TD/doc/product/software/ios122/122newft/122tcr/122twr/wftbrda.htm#1064471

  I'm looking to explain why this reduced MTU size worked. I would of never figured this out on my own...

  Here's the running-config, we used. Don't forget that everything worked (switching between WAN, vpn, NAT connectivity link) except the transfer of files and when large amounts of data was pushed over the line as MS-sharing files/printers, emails with attachments (a few hundred k). The only change is a line at the fa0 interface.

  version 12.2

  horodateurs service debug uptime

  Log service timestamps uptime

  encryption password service

  !

  hostname HPARFD

  !

  queue logging limit 100

  logging buffered debugging 8192

  enable secret 5

  enable password 7

  !

  abc username password

  clock timezone CST - 6

  clock to summer time recurring CDT

  AAA new-model

  !

  !

  AAA authentication login userauthen local

  AAA authorization groupauthor LAN

  AAA - the id of the joint session

  IP subnet zero

  !

  !

  no ip domain search

  IP domain name blahblah.net

  IP-name server

  IP-name server

  !

  audit of IP notify Journal

  Max-events of po verification IP 100

  property intellectual ssh time 60

  !

  !

  !

  !

  crypto ISAKMP policy 1

  md5 hash

  preshared authentication

  !

  crypto ISAKMP policy 2

  md5 hash

  preshared authentication

  !

  crypto ISAKMP policy 3

  BA 3des

  preshared authentication

  Group 2

  !

  crypto ISAKMP policy 10

  md5 hash

  preshared authentication

  test3030 key crypto isakmp address No.-xauth

  ISAKMP crypto key address 0.0.0.0 test3131 0.0.0.0

  crypto ISAKMP client configuration address pool local ourpool

  !

  ISAKMP crypto client configuration group whatever

  key

  pool ourpool

  ACL 101

  !

  !

  Crypto ipsec transform-set esp - esp-md5-hmac rptset

  Crypto ipsec transform-set esp - esp-md5-hmac trans2

  Crypto ipsec transform-set esp-3des esp-md5-hmac v35clientset

  !

  Crypto-map dynamic dynmap 10

  Set transform-set v35clientset

  Crypto-map dynamic dynmap 20

  Set transform-set trans2

  !

  !

  card crypto rtp-address Loopback0

  crypto isakmp authorization list groupauthor rtp map

  client configuration address card crypto rtp initiate

  client configuration address card crypto rtp answer

  RTP 1 ipsec-isakmp crypto map

  defined by peers

  Set transform-set rptset

  match address 115

  map rtp 50-isakmp ipsec crypto dynamic dynmap

  !

  !

  !

  !

  interface Loopback0

  Description loopback address is NOT dependent on any physical interface

  IP 255.255.255.255

  no ip proxy-arp

  NAT outside IP

  No cutting of the ip horizon

  !

  interface Ethernet0

  secondary description - wireless WAN link

  255.255.255.252 IP address

  no ip proxy-arp

  NAT outside IP

  No cutting of the ip horizon

  Half duplex

  crypto rtp map

  !

  interface FastEthernet0

  Description connected to EthernetLAN

  IP 255.255.255.0

  no ip proxy-arp

  IP tcp adjust-mss 1300

  ^ ^ ^ Tac added cisco work around

  IP nat inside

  automatic speed

  !

  interface Serial0

  first link description WAN - t1

  255.255.255.252 IP address

  no ip proxy-arp

  NAT outside IP

  random detection

  crypto rtp map

  !

  router RIP

  version 2

  passive-interface Loopback0

  passive-interface Serial0

  passive-interface Ethernet0

  network

  No Auto-resume

  !

  IP local pool ourpool

  IP nat inside source overload map route sheep interface Loopback0

  IP classless

  IP route 0.0.0.0 0.0.0.0 Serial0

  IP route 0.0.0.0 0.0.0.0 Ethernet0

  IP route 255.255.255.0 Serial0

  IP route 255.255.255.0 Ethernet0 200

  IP route 255.255.255.0 Serial0

  IP route 255.255.255.0 Ethernet0 200

  IP route 255.255.255.0 Serial0

  IP route 255.255.255.0 Ethernet0 200

  no ip address of the http server

  no ip http secure server

  !

  !

  !

  remote_access extended IP access list

  permit tcp any any eq 22

  permit tcp 0.0.0.255 any eq telnet

  TCP refuse any any eq telnet

  allow an ip

  !

  access-list 1 permit 0.0.0.255

  access-list 100 permit ip 192.168.0.0 0.0.0.255 host

  access-list 100 permit ip 192.168.0.0 0.0.0.255 host

  access-list 100 permit ip 192.168.0.0 0.0.0.255 host

  access-list 101 permit ip 0.0.0.255 10.2.1.0 0.0.0.255

  access-list 101 permit ip 192.168.0.0 0.0.255.255 10.2.1.0 0.0.0.255

  access-list 199 permit tcp a whole Workbench

  access-list 199 permit udp any one

  access-list 199 permit esp a whole

  access-list 199 permit ip 192.168.0.0 0.0.0.255 0.0.0.255

  !

  sheep allowed 10 route map

  corresponds to the IP 110

  !

  Enable SNMP-Server intercepts ATS

  RADIUS server authorization allowed missing Type of service

  alias exec sv show version

  alias exec sr show running-config

  alias exec ss show startup-config

  alias con exec conf t

  top alias show proc exec

  alias exec br show ip brief inter

  !

  Line con 0

  exec-timeout 0 0

  password 7

  line to 0

  line vty 0 4

  exec-timeout 0 0

  password 7

  Synchronous recording

  transport input telnet ssh rlogin udptn stream

  !

  NTP-period clock 17180059

  NTP server

  end

  You can check the following site for more explanation:

  http://www.Cisco.com/en/us/Tech/tk827/tk369/technologies_tech_note09186a0080093f1f.shtml

  HTH...