D&D 5E Standard security features of a permanent Teleportation Circle

[Saeviomagy]

Putting a circle outside the walls and then not securing it is still a massive security risk. Each casting of teleport circle can dump about 2000 well organised troops through. You really don't want to be defending a kingdom where the enemy can move troops like that, especially since they can follow that with a casting of private sanctum to stop you responding.

 

[Blue]

I agree with those who've said that PTCs need to go outside your defences - your castle or city walls. Having one inside the building will always be a major weakness and should be avoided unless you are certain it can be kept secret, which seems unlikely - if the enemy capture someone who knows the address they are likely to be able to charm/interrogate/torture them & get the code.

Outside defenses defeats some of the points. Say you are under siege you've just denied yourself use of it, both outgoing for your casters who can cast 5th but not yet 7ths, and incoming. Can't bring in reinforcements or anything. Heck, at that point your enemy may get more use from your expensive-to-create circle than you.

 

[S'mon]

Outside defenses defeats some of the points. Say you are under siege you've just denied yourself use of it, both outgoing for your casters who can cast 5th but not yet 7ths, and incoming. Can't bring in reinforcements or anything. Heck, at that point your enemy may get more use from your expensive-to-create circle than you.

That seems a fair point. I tend to think a world with common TP circles would look very alien.

 

[Saeviomagy]

The party in one of my campaigns will very likely be making a teleportation circle on their airship permanent, which will remain secure by way of only the party members knowing that the circle exists since it is located in the private apartment the party keeps on the ship, where the crew and any passengers or intruders cannot easily access (it being hard to get on the ship unnoticed, and then to get away from designated areas unnoticed, and then not be spotted by someone going about their own business while you deal with the arcane locked door from the common area of the ship to the private area).

Scry is the same level as teleport circle, so assuming people will never see your circle is poor security, no matter what mundane precautions you take against it.

 

[Erik Westmarch]

Scry is the same level as teleport circle, so assuming people will never see your circle is poor security, no matter what mundane precautions you take against it.

Scry would only be able to help in an unusual circumstance. You can see creatures, but that only lets you learn the sigil sequence if the creature stays within 10' of the Circle for a full minute. You can see places, but only places you've seen in person before, so you'd probably already know the sequence. The only real time Scry would help is if you had been through the Circle before but were rushed through so you couldn't study it. Scry would let you go back and memorize the sigils.

if the defences are very effective, and the enemy can't simply infiltrate an agent, then an enemy who can and wants/needs to teleport into your temple will simply run the risk of teleporting in based on a description. The (probably not fatal) risk of a mishap when teleporting via description is much better odds than certain death via a trapped permanent circle. Especially, if the first person teleporting is a minion/scout; who can purloin an object, which the main enemy force can subsequently use to return via error free teleports.

Presuming that Private Sanctum hasn't been cast over the whole area, right? That defeats Teleport, Scrying, and most methods of observation from outside the Sanctum.

You raise a really good point though, that the defenses of the Circle have to consider the "substitution effects". Once you've defended the Circle enough to discourage its use by strangers (and encouraged them to use other means to sneak into the area) there's no point in defending it any further. Or being a hazard to yourself.

Let's run down the list:

Good list, and excellent point that many destinations will have a mix of public and private spaces. The main weakness I see of having a relatively unguarded Circle in one of the public spaces is the change that a deliberate spy will come through already covered in Invisibility, Silence, etc. will be close enough to the sneak into the secure areas with the spells still effective. But I guess you run the same risk as someone just walking into the area and ducking behind a wagon to quaff a few potions, so maybe that's good enough.

Castle or Keep: This is the sort of place where you probably mix physical security with a social element - you put the circle either in an open area like a courtyard or bailey that is under watch of guards, or you put it in an isolated locked chamber with guards positioned outside and the best lock you can afford on the door, and you keep the sigil sequence a secret only a few people share. That way anyone wanting to use the circle has to not only know the right sequence, they also have to have a key to the door (because the guards specifically do not have one as a security measure), and be on the list of persons the guards aren't meant to sound the alarm at the sight of.

Good thoughts. Probably a room in one of the towers of the curtain wall, with very thick interior walls. That way anyone who exits the room would exit into the main inner courtyard where anyone on watch on either the curtain wall or Keep wall would be able to see them.

The party in one of my campaigns will very likely be making a teleportation circle on their airship permanent

Huh! I hadn't every thought of putting a permanent Circle in a thing that moves, but I guess there's no rule against it. Cool idea.

 

[Ahglock]

Putting a circle outside the walls and then not securing it is still a massive security risk. Each casting of teleport circle can dump about 2000 well organised troops through. You really don't want to be defending a kingdom where the enemy can move troops like that, especially since they can follow that with a casting of private sanctum to stop you responding.

You and I have vastly different opinions on how many people can get through a 10' portal in 6 seconds.

 

[the Jester]

I wouldn't allow a player to say "I get to pick the sigil I know, so I pick the master villain's secret base circle". The DM should provide them with the code for a circle useful to the mage in the context of the game - presumably the one in their home town.

Whereas I often give them coordinates to circles in new or unknown areas of the milieu. Useful? Not so much. Cool hooks for exploration? Hells yeah!

 

[dmnqwk]

I like to think of Teleportation Circles as a variant of Stargates.

Each TPC has an "address" which is geographically represented by the sigils, meaning it would be possible for a player to figure out how to access a TPC by way of knowing it's location and attempting to teleport there (though the chance of an accidental teleport akin to the old system would be more fun here).

On top of it, I would have each TPC vary in location as well as protection, for example:

1) The PCs find a TPC address written on a strange flyer, written in an obscure dialect of Gnomish. They attempt to contact it (with no chance of failure due to the exact address) and find themselves in a shopping emporium, located in a strange city where everyone is a curious mixture of human and dwarven blood.
2) A dying man lies on the side of the road, beaten heavily. Before he passes away, he tells the PCs about an ordinary-looking mansion which harbours a cult of yuan-ti. He tells them about a TPC located beneath the south wing of the dwelling. If they try to teleport to it without properly researching it's location their address will be inaccurate, allowing them a higher chance of failure (and possibly a catastrophic failure chance) than if they spent time getting plans of the house, finding a map of the area or having a single rogue sneak in to explore.

I know the TPC isn't directly written to function in this manner, but I do miss the old chance of teleport going a-wry, as well as ensuring that the TPC opens up a new system of exploration and adventure.

 

[Gadget]

I can't check right now, but couldn't you cover the circle with a rug and still have it function? That way people coming in would have no opportunity to learn the sequence, and things like Scrying would not work either. That would go along way to keeping the sequence secure.

 

[AaronOfBarbaria]

Scry is the same level as teleport circle, so assuming people will never see your circle is poor security, no matter what mundane precautions you take against it.

Scry, as Erik points out, isn't actually that big of a risk in this situation - especially considering the majority of the people that might like to scry on the party don't know them well enough nor have much of a connection to avoid the party member they choose to scry upon having a bonus on the saving throw to avoid it.

Plus, scrying is thwarted by Mordenkainen's private sanctum which can also be made permanent.