the first thing you likely do is op yourself so you can do commands in the game you can do this by typing the following command op [playername] in consol (for a full list of command’s visit this link)
open up server.properties the following is a default config
#Minecraft server properties
#Sat Jun 20 18:29:30 IST 2015
motd=A Minecraft Server
|allow-flight||false||Allows users to use flight on your server while in Survival mode, if they have a mod that provides flight installed.With allow-flight enabled griefers will possibly be more common, because it will make their work easier. In Creative mode this has no effect.
|allow-nether||true||Allows players to travel to the Nether.|
|announce- player-achievements||true||Allows server to announce when a player gets an achievement.|
|difficulty||1||Defines the difficulty (such as damage dealt by mobs and the way hunger and poison affects players) of the server.
|enable-query||false||Enables GameSpy4 protocol server listener. Used to get information about server.|
|enable-rcon||false||Enables remote access to the server console.|
|enable-command-block||false||Enables command blocks|
|force-gamemode||false||Force players to join in the default game mode.
|gamemode||0||Defines the mode of gameplay.
|generate-structures||true||Defines whether structures (such as villages) will be generated.
Note: Dungeons will still generate if this is set to false.
|generator-settings||blank||The settings used to customize world generation. See Superflat and Customized for possible settings and examples.|
|hardcore||false||If set to true, players will be permanently banned if they die.|
|level-name||world||The “level-name” value will be used as the world name and its folder name. You may also copy your saved game folder here, and change the name to the same as that folder’s to load it instead.
|level-seed||blank||Add a seed for your world, as in Singleplayer.
|level-type||DEFAULT||Determines the type of map that is generated.
|max-build-height||256||The maximum height in which building is allowed. Terrain may still naturally generate above a low height limit.|
|max-players||20||The maximum number of players that can play on the server at the same time. Note that if more players are on the server it will use more resources. Note also, op player connections are not supposed to count against the max players, but ops currently cannot join a full server. Extremely large values for this field result in the client-side user list being broken.|
|max-tick-time||60000||The maximum number of milliseconds a single tick may take before the server watchdog stops the server with the message, A single server tick took 60.00 seconds (should be max 0.05); Considering it to be crashed, server will forcibly shutdown. Once this criteria is met, it calls System.exit(1).
|max-world-size||29999984||This sets the maximum possible size in blocks, expressed as a radius, that the world border can obtain. Setting the world border bigger causes the commands to complete successfully but the actual border will not move past this block limit. Setting the max-world-size higher than the default doesn’t appear to do anything.Examples:
|motd||A Minecraft Server||This is the message that is displayed in the server list of the client, below the name.
|network-compression-threshold||256||By default it allows packets that are n-1 bytes big to go normally, but a packet that n bytes or more will be compressed down. So, lower number means more compression but compressing small amounts of bytes might actually end up with a larger result than what went in.
Note: The Ethernet spec requires that packets less than 64 bytes become padded to 64 bytes. Thus, setting a value lower than 64 may not be beneficial. It is also not recommended to exceed the MTU, typically 1500 bytes.
|online-mode||true||Server checks connecting players against Minecraft’s account database. Only set this to false if your server is not connected to the Internet. Hackers with fake accounts can connect if this is set to false! If minecraft.net is down or inaccessible, no players will be able to connect if this is set to true. Setting this variable to off purposely is called “cracking” a server, and servers that are presently with online mode off are called “cracked” servers, allowing players with unlicensed copies of Minecraft to join.
|op-permission-level||4||Sets permission level for ops.
|player-idle-timeout||0||If non-zero, players are kicked from the server if they are idle for more than that many minutes.
|pvp||true||Enable PvP on the server. Players shooting themselves with arrows will only receive damage if PvP is enabled.
|query.port||25565||Sets the port for the query server (see enable-query).|
|rcon.password||blank||Sets the password to rcon.|
|rcon.port||25575||Sets the port to rcon.|
|resource-pack||blank||Optional URI to a resource pack. The player may choose to use it.|
|resource-pack-hash||blank||Optional SHA-1 digest of the resource pack, in lowercase hexadecimal. It’s recommended to specify this. This is not yet used to verify the integrity of the resource pack, but improves the effectiveness and reliability of caching.|
|server-ip||blank||Set this if you want the server to bind to a particular IP. It is strongly recommended that you leave server-ip blank!
|server-port||25565||Changes the port the server is hosting (listening) on. This port must be forwarded if the server is hosted in a network using NAT (If you have a home router/firewall).|
|snooper-enabled||true||Sets whether the server sends snoop data regularly to http://snoop.minecraft.net.
|spawn-animals||true||Determines if animals will be able to spawn.
Tip: if you have major lag, turn this off/set to false.
|spawn-monsters||true||Determines if monsters will be spawned.
This does nothing if difficulty = 0 (peaceful) Unless your difficulty is not set to 0, when a monster can still spawn from a Monster Spawner. Tip: if you have major lag, turn this off/set to false.
|spawn-npcs||true||Determines if villagers will be spawned.
|spawn-protection||16||Determines the radius of the spawn protection. Setting this to 0 will not disable spawn protection. 0 will protect the single block at the spawn point. 1 will protect a 3×3 area centered on the spawn point. 2 will protect 5×5, 3 will protect 7×7, etc. This option is not generated on the first server start and appears when the first player joins. If there are no ops set on the server, the spawn protection will be disabled automatically.|
|use-native-transport||true||Linux server performance improvements: optimized packet sending/receiving on Linux
|view-distance||10||Sets the amount of world data the server sends the client, measured in chunks in each direction of the player (radius, not diameter). It determines the server-side viewing distance. (see Render distance)10 is the default/recommended. If you have major lag, reduce this value.|
|white-list||false||Enables a whitelist on the server.With a whitelist enabled, users not on the whitelist will be unable to connect. Intended for private servers, such as those for real-life friends or strangers carefully selected via an application process, for example.
Note: Ops are automatically white listed, and there is no need to add them to the whitelist.