Service Tag

A Service Tag is a tag meant to identify players quickly during a match. They consist of one letter and two numbers in Halo 3 and an arbitrary combination of 4 letters or numbers in Halo 3: ODST, Halo: Reach, and Halo 4. In team games, they appear above a player's head with a marker indicating their position, even through walls. When the player's reticle is pointed directly at the player, the full Gamertag is displayed instead.
It is beneficial for a player to set his service tag to be identical to his Gamertag so his teammates can more easily identify him.
==List of Prohibited Service Tags==
Some service tags are not allowed because they are vulgar, offensive, reserved, or copyrighted. These are not complete lists and are added to over time.
===Halo 3===
*Every service tag ending in 00
*A01 - Resembles AOL
*A20
*A23 - Reserved by UNSC
*A55
*C17
*E51
*E74 - Resembles the Red Ring error code E-74
*E43 - Resembles 343 in 343 Guilty Spark
*F03 - Resembles Fallout 3
*F43
*F46
*F48
*F49
*I17
*L17 - Reserved by UNSC
*N34
*N64 - Represents Nintendo 64
*N84
*P51 - Resembles "PS1"
*P52 - Resembles "PS2"
*P53 - Resembles "PS3"
*T17
*U50
*V50
*Z17
*117 - Reserved by UNSC
===Halo 3: ODST===
*C0DY
*B4K4
*C0CK
===Halo: Reach===
*S117 - John-117's service number
*UNSC
*Sll - Resembles Spartan II
*7 - Bungie's favorite number
*0000
*Slll - Resembles Spartan III
*WIKI - Used by Halo Nation members
*RVB - Stands for Red vs Blue, a machinima series by Rooster Teeth
*343I - Stands for 343 Industries
*AN - Stands for Allied Nations
*NOOB
*HALO
*JOHN
*YIFF
===Halo 4===
*343I - Stands for 343 Industries
==Trivia==
*In Halo 3, when I17 is entered as a service tag, a message displays that says, "this service tag is currently reserved by the UNSC."
*A prohibited service tag can be used if it was randomly assigned to the player upon profile creation.
==Sources==
Category:Halo 3 Multiplayer
Category:Firefight
Category:Halo: Reach Multiplayer
Category:Halo 4 Multiplayer
Category:Spartan Ops