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TsooRad is a blog for John Weber. John is a Skype for Business MVP (2015-2018) - before that, a Lync Server MVP (2010-2014). My day job is titled "Technical Lead, MS UC" - I work with an awesome group of people at CDW, LLC. I’ve been at this gig in one fashion or another since 1988 - starting with desktops (remember Z-248’s?) and now I am in Portland, Oregon. I focus on collaboration and infrastructure. This means Exchange of all flavors, Skype, LCS/OCS/Lync, Windows, business process, and learning new stuff. I have a variety of interests - some of which may rear their ugly head in this forum. I have a variety of certifications dating back to Novell CNE and working up through the Microsoft MCP stack to MCITP multiple times. FWIW, I am on my third career - ex-USMC, retired US Army. I have a fancy MBA. One of these days, I intend to start teaching. The opinions expressed on this blog are mine and mine alone.

2013/12/31

DHCP option 002 for Lync phones

Maybe I have been living under a rock… but I have been doing this manually… finally found a nifty chart so I can stick it in OneNote instead of having to figure it out each time – complete with instructions on how to calculate manually.  I take no credit, this is blatantly cut from a Cisco website source.

Standard Pacific time is GMT -8. This is a simpler way to calculate GMT with negative values:

1. The number of seconds equivalent to - 8 hours = - 8 hours * (3600 seconds / hr) = - 28800 seconds.

2. With a scientific calculator, enter the number -28800 in the calculator with decimal values. The (-) sign is very important. In order to get the negative sign in front, press the +/- key.

3. Choose Hex. This gives you FFFFFFFFFFFF8F80. This is because, by default, the calculator has Qword enabled.

4. In order to get rid of the extra Fs, choose Dword. This produces the value FFFF8F80. If you do not have this option in your calculator, use only the first eight digits from right to left.

5. The value placed in the DHCP pool configuration now becomes option 2 hex FFFF.8F80.

 

Table of Conversion of Different Offset Times into Hexadecimal

This table gives the conversion of the different time zones around the world. The hexadecimal values are set to have a fixed length of 32 bits as specified in Option 2 of the DHCP RFC 2132. For a world timezone map, refer to World Time Zone Map.

GMT offset (in hr)

GMT offset in seconds

GMT offset in Hexadecimal

0

0

0000.0000

+1

3600

0000.0E10

+2

7200

0000.1C20

+3

10800

0000.2A30

+4

14400

0000.3840

+5

18000

0000.4650

+6

21600

0000.5460

+7

25200

0000.6270

+8

28800

0000.7080

+9

32400

0000.7E90

+10

36000

0000.8CA0

+11

39600

0000.9AB0

+12

43200

0000.A8CD

-1

-3600

FFFF.F1F0

-2

-7200

FFFF.E3E0

-3

-10800

FFFF.D5D0

-4

-14400

FFFF.C7CD

-5

-18000

FFFF.B9B0

-6

-21600

FFFF.ABA0

-7

-25200

FFFF.9D90

-8

-28800

FFFF.8F80

-9

-32400

FFFF.8170

-10

-36000

FFFF.7360

-11

-39600

FFFF.6550

Example

Pacific Time Zone = GMT –8

60*60*8 = 28800.  Change sign. Now we have –28800.

image

Click the Hex button.  Now we have

image

Click the DWord button.  Now we have

image

Here is the value in the DHCP Server Options. Note that we take the DWord value and append “0x” to it.

image

YMMV

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