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Getting jumbo frames working on LAN?

It's not working but I have jumbo frames turned on everywhere.  What am I missing?
C:\Users\>ping -f -l 6000 rabbithill -t

Pinging rabbithill [] with 6000 bytes of data:
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.

Ping statistics for
    Packets: Sent = 3, Received = 0, Lost = 3 (100% loss)

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Here's the config on two Win7 computers.
Here's the config on the router (Cisco ASA5505 which supports jumbo frames per link here) the two machines are connected via:
ciscoasa# show interface
Interface Ethernet0/0 "", is up, line protocol is up
  Hardware is 88E6095, BW 100 Mbps, DLY 100 usec
        Auto-Duplex(Full-duplex), Auto-Speed(100 Mbps)
        Input flow control is unsupported, output flow control is unsupported
        Available but not configured via nameif
        MAC address 001d.7026.4a75, MTU not set
        IP address unassigned
        6261730 packets input, 4479205417 bytes, 0 no buffer
        Received 0 broadcasts, 0 runts, 0 giants
        0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
        0 pause input, 0 resume input
        0 L2 decode drops
        2 switch ingress policy drops
        5776171 packets output, 3963675140 bytes, 0 underruns
        0 pause output, 0 resume output
        0 output errors, 0 collisions, 0 interface resets
        0 late collisions, 0 deferred
        0 rate limit drops
        0 switch egress policy drops
        0 input reset drops, 0 output reset drops

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Geoff Millikan
Geoff Millikan
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3 Solutions
Geoff MillikanAuthor Commented:
Opps, jumbo frames arn't supported on Cisco ASA5505.  Dang.  From the manual:

Enabling Jumbo Frame Support (Supported Models)

A jumbo frame is an Ethernet packet larger than the standard maximum of 1518 bytes (including Layer 2 header and FCS), up to 9216 bytes. You can enable support for jumbo frames for all interfaces by increasing the amount of memory to process Ethernet frames. Assigning more memory for jumbo frames might limit the maximum use of other features, such as access lists.

Supported models include:

•ASA 5512-X

•ASA 5515-X

•ASA 5525-X

•ASA 5545-X

•ASA 5555-X

•ASA 5580

•ASA 5585-X

TimotiStDatacenter TechnicianCommented:
100Mbps interfaces rarely support jumbo:
  Auto-Duplex(Full-duplex), Auto-Speed(100 Mbps)
  MAC address 001d.7026.4a75, MTU not set

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And you most likely want them only inside a subnet: a firewall needs to look at the entire packet for inspection, so it might add to the delay if it has to deal with big frames.
Also, don't forget that every switch needs to support (capable and enabled) them along the way.
Davis McCarnOwnerCommented:
So spend $25 and take the Cisco out of the packet loop: http://www.newegg.com/Product/Product.aspx?Item=N82E16833704043&Tpk=N82E16833704043

Plug one of the Cisco's lan ports and all of the PC's into a gigabit switch and voilla!
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Geoff MillikanAuthor Commented:
Does the Linksys SE3016 support jumbo frames?  That's our core office switch but I'll be picking up a TP-LINK TL-SG1008D too.  

Great ideas!  Thank you!
Davis McCarnOwnerCommented:
Yes, the Linksys SE3016 supports jumbo frames so, if all of the network devices are connected to it, you should be working.
Jumbo frames only helps with large file transfers across the network.  Tell me more about what your need is and what problems you are having with it.
Geoff MillikanAuthor Commented:
Awesome.  Usage = lots of large file size transfer thru the office LAN due to database backups.  Since our LAN is all in one office, ping times are very fast so not expecting to see a huge performance lift from this, mostly just curious.  If we had nation-wide LAN, this would be a bigger issue.
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