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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;">If you are not doing SAN stuff, or very large file transfers within the collision domain - enabling Jumbo is likely to cause a crappier performance than leaving it at the standard
1500MTU - because, the router or receiving device will tell the sender to fragment, your packet will be split in half, this retransmit attempt will happen several times till the MTU is met - then as the "knowledge" of this expires your device will have to
do that over and over.. causing a ton of extra traffic on your network.. so, if you don't have a requirement to use large MTU, then turn it off - i suspect there are mechanisms in the vpn software that either ignores large packets (because they are not to
be routed) or just can't handle fragmentation at that level<br>
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<div style="direction: ltr;" id="divRpF886705"><font color="#000000" face="Tahoma" size="2"><b>From:</b> Paul Theodoropoulos [paul@anastrophe.com]<br>
<b>Sent:</b> Friday, October 25, 2013 1:15 PM<br>
<b>To:</b> Thomas Stokkeland; vpn-help@lists.shrew.net<br>
<b>Subject:</b> Re: [vpn-help] No connect when configured for jumbo frames<br>
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<div><font face="Georgia">Except that all of my other connectivity was unaffected, which is why I posted to the list. It seemed specific to shrew. But I did a little further reading, and it does seem that jumbo's simply aren't relevant outside of LAN-to-LAN
communication, so it's fairly pointless to use them outside of that need.<br>
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<div class="moz-cite-prefix">On 10/25/13, 5:09 AM, Thomas Stokkeland wrote:<br>
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<blockquote type="cite">I dont know anything about Jumbo's in the context of IPSec - but in general, Jumbo's is only for SAN traffic, a packet larger than 1500 is generally not routable - so it makes sense to me that a large MTU will break any type of connectivity
on layer 3 outside the local subnet and collision domain. <br>
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On 10/25/2013 2:56 AM, Paul Theodoropoulos wrote: <br>
<blockquote type="cite">Just discovered purely by accident that if I configure my ethernet adapter to use 9k jumbo frames (same as my gb ethernet switch supports), Shrew will 'reliably' fail to establish any part of a connection. Reconfiguring the adapter to
jumbo frames disabled restores ability to connect. <br>
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Odd. Thoughts? <br>
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<pre class="moz-signature" cols="72">--
Paul Theodoropoulos
<a class="moz-txt-link-abbreviated" href="http://www.anastrophe.com" target="_blank">www.anastrophe.com</a></pre>
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