IPv6 contact for www.citrix.com - MTU problem?

[Daniel Roesen]

On Wed, Aug 17, 2011 at 08:41:35PM -0400, Brandon Applegate wrote:
> The dns hostnames seem to indicate they are doing GSLB (I assume netscaler, 
> dog food, etc).  Perhaps you are getting a different answer from where you 
> are and there is indeed an MTU problem on whatever instance you are talking 
> to.

$ dig www.citrix.com AAAA +short
www.gslb.citrix.com.
2001:1890:111e:201::15

So mapping to same IPv6 address.

> Even though I can't recreate it, hopefully some of this information helps. 
> I'm curious to see what else you find out.

Thanks for helping!

Can you lower your own end's tunnel MTU to 1280 and see what happens?
If their MSS is 1360, I guess their server NIC MTU is set to 1420 or
so - if this is lower than your tunnel MTU, you won't see any
fragmentation-related problems (their side not reacting to "frag needed"
ICMP) indeed.

Best regards,
Daniel

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