"...Well, I did say as much myself, a little while back, so I'd be a bit of a hypocrite to keep going now just because I think I have something that might work.  ...I'll have to investigate what wards Sauron has, anyway; I wouldn't be surprised if the present state of Valinor-and-or-Arda has ...inspired... him to defend against the relevant sorts of spatial disturbance..."

Gandalf raises his bushy eyebrows.  "I had not considered he might have tried to prepare against another Change of the World... but he was caught unprepared in the middle of the Change, so he might indeed."

Lindir looks surprised, but then nods.  "Feanor prepared in case Ungoliont attacked us again.  It would be ill-sighted to assume Sauron is less wise than him..."

"...The Valar are really not subtle."

"...Well, then!  That discounts arcane portals..."

She's going to need to work this out properly.

(...Lindir.  Lindir.  She cannot tell if you're damning with faint praise when you deliver something like that.  But right now she's too busy thinking about how void-portals should work to actually consider the question.)

"...safety concerns from a hostile teleport..."

"...but then we need to blind it anyway..."

"...echoes?  But that's already true, or λ-true as the case may be..."

She surfaces from her thoughts.

"...The question is whether Sauron is able to raise a similar defense against - things that are more like Ungoliant, magically speaking, than an equivalently strong Act of Valar or Eru.  My normal means of accomplishing such things is more like the latter, from what little I know of how any of that could possibly work, but - there is a different sort of power I also know how to use, that seems similar enough that if Sauron can't or doesn't ward against Ungoliant, it might also slip through."

"Certainly some have speculated that the reason that he lets a giant spider lurk in the back way to Mordor is because if it came to a fight between him and Ungoliant he'd get squished.  But we don't know that, we certainly can't prove it, and that doesn't necessarily mean that we're in any position to make use of that information even if those people happen to be right.  It's not as if I'm working with a power differential as she would be."

"I certainly don't think, though, that he could be expecting that sort of magic to make something that would, in raising defenses against the things I know happened, defend against a portal made through - similar forces.  It's not as if Ungoliant can teleport, that I know of.  ...That doesn't mean he didn't speculatively do so, or that I am not misinformed about whether Ungoliant's feats include teleportation - I was not there - but I can't say I think it particularly likely that he would, and that he would actually figure out the right way to do such a thing if he did try, though now that I'm thinking about it he is a rogue Maia, and it's not as if...  Hm.  But no, I don't think he'd have practical experience...  Certainly one would not have expected Morgoth to need Ungoliant's help, otherwise...  ...Still, it's not like I've done that before except by the very accident that landed me here, so that's a risk of its own, even considering that I do have actual control structures for this that weren't active during that accident..."

"...Anyway.  I'll need to get back to you on the feasibility of that one, when we meet again."

"...We still haven't discussed Moria, have we?  As much as none of that is going to be good news."