Does moving behind full cover count as “leaving the opponent’s reach” for purposes of Attack of Opportunity?

Suppose I am fighting an enemy with the usual 5-foot reach. He is standing next to a wall beside an open doorway. I am in next to him in the room. Without leaving his 5-foot range, I move to the other side of the wall. Does he get an attack of opportunity?

                                                 M --------  -----    to  --------M -----  to--------  -----            EM                     E                  E 

Assume that the wall is only a foot thick and is halfway in E’s square and halfway in mine, so that E(nemy) and M(e) are in adjacent squares in the final diagram. But the enemy cannot reach me through the wall, so have I “left his reach” taking an attack of opportunity while in the doorway?

If there was no wall there, I could move to that position without provoking any opportunity attack. Does the wall being there make it easier for the foe to attack me somehow?

Does your analysis change in the 3-dimensional case where the creature potentially leaving reach is an incorporeal creature moving from the square next to an enemy to the square (cube) next to and below the enemy?

Does Truesight allow you to see through or behind solid objects?

From what I understand in the references in the MM and PHB to Truesight, it seems that a creature with this sense can see into the Ethereal Plane and see invisible things/creatures. However, does this allow the creature to see through solid rock, e.g. if a PC was out of typical line of sight, with 100% cover, hiding behind a large tree or a stone pillar?

There was some confusion about this in a recent campaign. The way I would interpret it is that having Truesight does not allow a creature to see through objects, e.g. like x-ray vision. For me, seeing the "invisible" does not mean the same as seeing the "non visible".

I would appreciate any RAW answers using 5e literature and/or experience on applying a house-rule regarding this matter.

What’s behind the widespread negative response to Wild Sorcerers, and how can I ensure they’re fun at my table?

I’m just starting to get into D&D 5e. Magic classes in particular fascinate me, and the one that caught my eye the most is the wild sorcerer. Or, rather, the concept did. The mechanics of the design itself seem particularly lackluster when compared to every other magic class I’ve looked at.

After quite a bit of searching, it seems I’m not alone in this observation. All over the place, people insist that wild sorcerers are unbalanced/underwhelming/generally unwanted. But I haven’t really seen any explanations of what exactly makes them this way, compared to other classes.

I’m now looking at attempting to DM a game with a bunch of other newbies, and trying to figure the game out as a group. One of my players will likely want to play a wild sorcerer. I’m interested in seeing how that plays out in RAW, but more importantly, I want the players to have fun.

I’m new and inexperienced. What should I look out for in the Wild Sorcerer when considering balance, or fun? Are there any gaping flaws in practice for the wild sorcerer’s design?

Right now I’m considering using the existing mechanics, but supplementing them with a secondary system of character progression that slowly takes the sorcerer from fearing their magic that’s unpredictable, to having some, but not total, control over it. Basically there’s a chaos level that increases and decreases based on player ability/spell usage. High chaos means more wild surges, low means less. To get the most out of the design, you have to balance the chaos level (in theory).

Note, I’m well-aware that I should probably stick to RAW during the learning phase. But as someone that works in gaming, I’m also aware that mechanics typically function differently in practice than in theory, and so I want to be prepared for any known “in-practice” shortcomings.

It sounds like the main ones are how often a surge happens (GM overhead, chance of anything happening at all), and exactly what happens (more flavor vs more functionality, which is up to what you want from the game). Both answers were solid, but I’m going with Icy’s, since it approached the question more specifically targeting the Wild Sorcerer’s in-practice functionality with examples and edge cases.

What is the intuition behind Strassen’s Algorithm?

I came across Strassen’s algorithm for matrix multiplication, which has time complexity $ O(n^{2.81})$ , significantly better than the naive $ O(n^3). Of course, there have been several other improvements in matrix multiplication since Strassen, but my question is specific to this algorithm.

If you see the algorithm, you’ll notice that 7 matrices $ M_1$ to $ M_7$ have been defined as intermediate computation steps, and the final matrix product can be expressed in terms of these. I understand how to verify this claim, and arrive at the expression for the desired time complexity, but I’m unable to grasp the intuition behind this algorithm, i.e. why are the matrices $ M_1$ through $ M_7$ defined the way they are?

Thank you!

What is the mathematics behind Facebook friend suggestion algorithms [closed]

Can anyone help me know how Facebook suggests unknown friends? Or, any references in this regards will do.

What i know is there are infinite ways in which Facebook can suggest friends. One of the ways in which Facebook suggests you friends is that when that person has mutual friends with you or that person is directly or indirectly connected your friendship networks (even if you have no mutual friends with him). In the line of this algorithm, i am thinking of a an algorithm to predict friend suggestion by Facebook using graphs and its union and intersection operations.

My problem is that, i couldn’t find any Mathematical algorithms of the mechanisms of friend suggestion by Facebook. Any reference in this regards will be appreciated.

How to ban IP address behind NAT

I am creating WebSocket server with rust and tokio and I want to prevent DDos attacks and spams.

So I thought of creating HashMap and inserting IP address which i suspect are trying to do spamming or DDos Attack but will this also ban other innocent users sharing same NAT network with attacker ?

If I ban IP address and port combination, will the attacker just use other port?

What’s the purpose behind this phishing attempt?

As probably all of you, I got an email that was intended as a phishing attack.

The HTML version of the email was pretending to be a Facebook email of a security warning.

phishing image

The links do lead to Facebook, for an account-switching crafted URL. I get that one.

However, the text version of the email has something like this:;;;;;;;;;;;;;; 

(I redacted out usernames from those addresses.)

Some of those names seem to be related (maybe the same person across multiple domains?). Some others seem generic but on a similar vein (mostly universities).

My question is: what’s the purpose of this "attack"? Clicking on those would trigger my email client to prepare an email for all those addresses. What does an attacker gain out of this?

Reverse shell from behind NAT and Firewall

I am new here so I apologize for not providing complete details. Let me explain you the problem now. I was working on Ganana 1 CTF challenge. To up the challenge, I decided to place this CTF machine behind a router. My entire LAB is on Vmware. For this scenario, I used three virtual machines : Kali, Ipfire and Ganana 1 CTF machine.

Kali Linux is my attacker machine which received its IP from VMWARE NAT (

Ipfire is installed as a router cum firewall with RED + GREEN configuration. The RED (external) interface received its IP address ( from Vmware NAT and for the GREEN interface IPfire acts as a DHCP server (

Now, I connected Ganana CTF machine to the GREEN interface of the IPfire. It’s IP address is

The GREEN interface is allowed to have internet. Now, when I port scanned the Ganana CTF machine from my kali, port 80can be accessed. As part of the challenge, I got access to the wordpress installation on the target machine. It is here I decided to edit 404.php page to change the code to that of php reverse shell by pentest monkey. I configured it to connect to my attacker machines’ IP address ( port 1234. But the reverse shell is not working. However, when kali and Ganana 1 are placed on the same network (NAT) the shell is working.

What is the mistake I am making?

Reverse shell from behind firewall and NAT

I have been working on a cyber security project in which I placed a web server behind ipfire router ( external IP This is part of a GREEN LAN network (say IP IS I am trying to get a reverse shell from this target web server to my attacker machine kali (ip CAN somebody help me in detail as how to get this reverse shell successfully?