To keep area files from stepping on each others vnums, there is a tradition of each zone being assign a two or three digit vnum as a 'starter', such as 42. Then, the zone is expected to make all vnums in the formst 42XX. When you start a new zone with MZF, it asks for the starter vnum. You are given 9900 as a default. If you start with that and go create 3 rooms, the rooms will be numbered 9900, 9901, and 9902. This is reasonable, except that everyone with MZF could start zones at 9900, and then collisions occur when the zones are put into play on the same server. For that reason, the best policy is to ask your IMP what vnum he wants you to use and start with that. If you don't know yet, start with 9900 and you can later renumber you zone with MZF.
The zones in stanard Merc 2.2 are the following
00 limbo.are... 20 catacomb.are 40 moria.are... 60 haon.are.... 80 -
01 smurf.are... 21 hood.are.... 41 moria.are... 61 haon.are.... 81 -
02 -........... 22 draconia.are 42 -........... 62 -........... 82 -
03 plains.are.. 23 mahntor.are. 43 -........... 63 arachnos.are 83 marsh.are
04 -........... 24 -........... 44 -........... 64 -........... 84 -
05 -........... 25 -........... 45 -........... 65 dwarven.are. 85 -
06 ofcol2.are.. 26 -........... 46 -........... 66 daycare.are. 86 dream.are
07 -........... 27 -........... 47 juargan.are. 67 -........... 87 -
08 -........... 28 trollden.are 48 -........... 68 -........... 88 -
09 olympus.are. 29 firenewt.are 49 -........... 69 -........... 89 grove.are
10 air.are..... 30 midgaard.are 50 eastern.are. 70 sewer.are... 90 -
11 shire.are... 31 midgaard.are 51 drow.are.... 71 sewer.are... 91 dylan.are
12 hitower.are. 32 midgaard.are 52 thalos.are.. 72 sewer.are... 92 canyon.are
13 hitower.are. 33 midgaard.are 53 mirror.are.. 73 sewer.are... 93 galaxy.are
14 hitower.are. 34 chapel.are.. 54 -........... 74 sewer.are... 94 mobfact.are
15 gnome.are... 35 midennir.are 55 ofcol.are... 75 -........... 95 -
16 wyvern.are.. 36 grave.are... 56 -........... 76 -........... 96 -
17 wyvern.are.. 37 school.are.. 57 -........... 77 -........... 97 -
18 -........... 38 -........... 58 -........... 78 valley.are.. 98 -
19 -........... 39 moria.are... 59 -........... 79 redferne.are 99 -
(Note that you can go past 99xx, all the way up to 326x).
When you are working with MZF, it will be generating vnums for you. You don't need to look at these numbers unless you are generating zones with a lot of 'similar' objects, such as two 'cityguards'. Then you can look at the numbers and tell which is which.
Sometimes if you look at the raw text for an area, you will see vnums with letters at the beginning, such as XX00 or QQ00. These zones have been made vnum neutral to allow anyone to put them into a server without conflict. The IMP looks up an empty vnum, and then replaces all occurances of (say) QQ with the code he has assigned. MZF will not read or write currently in the vnum neutral format.