How to find seed of server I am renting?

[gameguy430 0]

So I want to use the explore map cheat but can't on the server I am renting. Is there a way to get the seed of my server so I can make a new one? Then I could take a pic of the map on the personally hosted seed and use on my rented server.

[Blisto 4]

There might be another way around this.
The explored map area is stored in your character files and loaded in when it sees you connect to the same world. 

You can try to export the world to your local computer, if you don't already have an older version, then you can use the cheat in single player. If you save your character by logging out after youve used the cheat it should also be revealed when you connect to your hosted server. Even without uploading the World again. 

Haven't tried it myself but I think it should work. 
It doesn't matter if the world files are older or newer since it can see they are the same created world. 

[Chaos Crafter 1]

So I was wondering the same.
It turns out to be fairly easy but you need the right software - specifically you need an ftp client.  Personally I suggest WinSCP

So you are going to FTP to the server to pull down the .fwl file and then hand it to a system that extracts the seed.

Go to your control panel for the game (I'm assuming you have access - this won't work if you aren't the admin)
Keep it open so you can cut and paste, but for now find the section labeled FTP Details.  Here you will see the IP/Host, Port, User, and Password.

Now open your FTP client and create a new session.  Here are instructions for WinSCP
On opening WinSCP it will open a dialog titled "Login". 

1. Select "New Site"
2. Set File protocol to FTP
3. Copy the IP/Host value to host name
4. Make sure the Port number matches the Port value (they should both be 21)
5. Copy the User name and password.
6. If you're going to use this later (for eg, taking backups) select save.
7. Select Login

You will now be taken to the root (base) folder of your deployment.

From there you will se a file called something like 123456.fwl.  It is listed as 0 bytes because it's actually a link to the real file (I've not worked out where that one is)

If you take a local copy of that and the db file withit you have a backup of the server.

If you take that file and drop it into the box on http://valheim-map.world/getseed.html it will tell you your seed.  It will also give you a link to the map display utility.

Now if you haven't access to the .fwl file (because you're not admin or for some other reason) then I can't help you.

Best of Luck,