Update XVM renumbering FAQ for this year's episode

diff --git a/doc/xvm/renumbering.mdwn b/doc/xvm/renumbering.mdwn
index 66ae0aa0cbcc5ebdb1215e6705bc0eac541d8e41..e6142496f89000544b13596d9f114a29c95619c3 100644 (file)
--- a/doc/xvm/renumbering.mdwn
+++ b/doc/xvm/renumbering.mdwn
@@ -5,23 +5,15 @@ XVM's IP renumbering.
 
 [[!toc]]
 
-## What is this "renumbering" all about?
-
-As you may have heard, MIT has recently sold half of its IPv4 address space
-to Amazon in order to fund various network infrastructure upgrade projects.
-While there are enough remaining addresses for everyone and everything that
-was using one before, some rearrangement is required to make sure that
-everyone's IP addresses are in the smaller space that will be left after
-Amazon takes over the space that they have purchased.  That takeover will
-happen later in June.
-
-All of the IP addresses used by VMs on XVM since its inception were,
-unfortunately, in the part of MIT's IP address space that has been sold to
-Amazon, and thus all of our IP addresses need to change.  You can read the
-official explanation of this sale and MIT's upcoming network upgrades
-[here](https://ist.mit.edu/network/next-gen-mitnet-faq), but be sure to
-continue reading this FAQ, because IS&T's description of how the academic
-buildings and residence halls are being migrated does not apply to XVM.
+## What is this "renumbering" all about?  Didn't we already do this last year?
+
+If you were an XVM user one year ago, you may remember having your VM(s)
+renumbered from IP addresses beginning with `18.181` to IP addresses
+beginning with `18.49` back then.  We are being required to renumber
+again by IS&T.  Please contact IS&T if you have questions about why
+we are being required to renumber.  The process this time will be very
+similar, except that this time, addresses will be changing to ones beginning
+with `18.25`.
 
 ## Do I need to take any action?
 
@@ -81,14 +73,11 @@ your website as your VM migrates IP addresses.
 ## When will my IP addresses change?  Can I postpone this?  Can I migrate early?
 
 We plan to begin automated migrations of VMs to their new IP addresses on
-Monday, June 4, 2018.  This process is expected to take somewhere between
+Monday, August 5, 2019.  This process is expected to take somewhere between
 a few days and one week.
 
 There are several forces at play that we do not control, so there is very
-limited flexibility that we can offer.  Amazon will take control of the
-space that they have purchased on June 26, 2018.  IS&T needs SIPB and XVM to
-vacate our old IP space well before then so that they can carry out various
-preparatory tasks before the official transfer to Amazon.
+limited flexibility that we can offer.
 
 If your VM requires special coordination in order to be migrated, we will
 work with you to find a time that works well, possibly earlier than the
@@ -104,12 +93,13 @@ be ready for it to be migrated.
 
 ## What will my new IP address be?  How can I tell if my migration has happened?
 
-Your old IP address was of the form `18.181.xxx.yyy`.  Your new IP address
-will be of the form `18.49.xxx.yyy` where `xxx` and `yyy` will remain the
-same.  If your VM's networking is statically configured and you will be
-updating this info manually because you cannot switch to using DHCP, it
-is critical that you note that the gateway and netmask will also be changing.
-Please see the question on what to do if you use static addressing below.
+Your old IP address was of the form `18.49.xxx.yyy`.  Your new IP address
+will be of the form `18.25.zzz.yyy` where `yyy` will remain the same and
+`zzz` will be `xxx + 128`.  If your VM's networking is statically configured
+and you will be updating this info manually because you cannot switch to
+using DHCP, it is critical that you note that the gateway will
+also be changing.  Please see the question on what to do if you use static
+addressing below.
 
 Before your migration, you can see what your new network parameters will
 be by visiting XVM's website at <https://xvm.mit.edu/> and clicking the
@@ -118,7 +108,7 @@ begins with "Other Address:".
 
 Once your migration has occurred, the "IP:" line on the info page and
 the IP address on the line for your VM on XVM's main webpage will show
-your new address, which begins with `18.49`.
+your new address, which begins with `18.25`.
 
 ## My VM's networking is statically configured.  What should I do?
 
@@ -134,8 +124,8 @@ at <https://xvm.mit.edu/> and click the link for your VM to go to its
 info page.  On that page, you will be able to see both the current and
 new IP address, netmask, and gateway.  There will also be a new button
 on the page with a message above it saying that you can reconfigure your VM 
-with the new IP parameters (make sure you get the netmask and gateway
-correct; they will not be the same as the old ones) and then click the
+with the new IP parameters (make sure you get the gateway
+correct; it will not be the same as the old one) and then click the
 button.  If your VM is running, clicking the button will powercycle your
 VM.  If your VM is not running, clicking the button will update XVM's
 configuration for your VM and tell you to turn it on to complete the
@@ -201,7 +191,7 @@ If you have questions that are not answered by this FAQ, you should
 contact us and we'll do our best to answer them.  If your VM requires
 special coordination (for example, due to any of the reasons listed in
 the "Do I need to take any action?" question near the top of this page),
-you should definitely contact us no later than Sunday, June 3.  If anything
+you should definitely contact us no later than Sunday, August 4.  If anything
 goes wrong during your VM's migration, again, we need to hear from you.
 Finally, if you have feedback about the process that you would like to share,
 we welcome you to contact us.