Re: MTU size

On Tue, Nov 19, 2013 at 3:37 PM, Larry DiBona <[email protected]> wrote:
> lost my password, cant log in to un subscribe please un subscribe

Please take a moment to read this:

To unsubscribe from Poptop-server, get a password reminder, or change
your subscription options enter your subscription email address:


>
>
> James Cameron wrote:
>
> Summary:
>
> The MTU should be left at 1500, or lowered to whatever works.
> You have to test with many many IP addresses to find the right MTU.
>
> Detail:
>
> When IP packets are sent over PPP, they grow slightly.  When the
> packets are then sent over GRE, they grow some more.  This growth
> makes them too big to fit in the usual 1500 limit.
>
> Normally, when everything is working correctly, the packets are split
> into two parts and sent one after the other, and then reassembled at
> the other side.
>
> Sometimes, the need to split the packets cannot be determined at the
> server or the client, because the need is recognised by a node in the
> network between the server and the client.  The need is transmitted in
> a separate message, called an ICMP Fragmentation Needed.  This message
> comes from a third-party to either the server or the client.
>
> Further, sometimes this message is blocked, by accident, by policy, by
> security.  When that happens, the server or the client don't know that
> their original packet didn't get through, and so the connection
> freezes.
>
> If lowering the MTU fixes the symptom, then it is a reasonable guess
> that the above description is the problem.
>
> You can find more on this at
> http://en.wikipedia.org/wiki/Path_MTU_Discovery
>
> On Tue, Nov 19, 2013 at 12:31:15PM +0000, Khapare Joshi wrote:
>
>
> Just curios what MTU size ppp server should be configured ?
>
> I see some of those ppp client has
>
>  UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1396  Metric:1
>
> UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1496  Metric:1
>
> Why this is ? should not be 1500 for every client that connect to vpn ?
>
> So the problem is some of my users can connect to my VPN server but they
> could
> not get anything such as website outside my company as an example.
>
>
>
>
>
> ------------------------------------------------------------------------------
> Shape the Mobile Experience: Free Subscription
> Software experts and developers: Be at the forefront of tech innovation.
> Intel(R) Software Adrenaline delivers strategic insight and game-changing
> conversations that shape the rapidly evolving mobile landscape. Sign up now.
> http://pubads.g.doubleclick.net/gampad/clk?id=63431311&iu=/4140/ostg.clktrk
> _______________________________________________
> Poptop-server mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/poptop-server
>

-- 
This e-mail (including any attachments) is for the sole use of the intended 
recipient(s) and may contain information that is confidential and/or 
protected by legal privilege. Any unauthorized review, use, copy, 
disclosure or distribution of this e-mail is strictly prohibited. If you 
are not the intended recipient, please notify Mitel immediately and destroy 
all copies of this e-mail.  Mitel does not accept any liability for breach 
of security, error or virus that may result from the transmission of this 
message.

------------------------------------------------------------------------------
Shape the Mobile Experience: Free Subscription
Software experts and developers: Be at the forefront of tech innovation.
Intel(R) Software Adrenaline delivers strategic insight and game-changing 
conversations that shape the rapidly evolving mobile landscape. Sign up now. 
http://pubads.g.doubleclick.net/gampad/clk?id=63431311&iu=/4140/ostg.clktrk