trying to prevent ddos with cisco pix 501
I am under DDoS. What can I do?
Did not receive site association bonus (+100 rep) I accidently ran  sudo chmod 755 -R /   instead of  sudo chmod 755 -R ./   I stopped it after few seconds, but now there is some problems such as  sudo: must be setuid root   How can I revert permissions back? Image, pre-image, and injection proof verification Just wanted to verify this proof was correct. Trying to make sure I have a handle on these subjects before the exam. Any style comments also more than welcome.    Statement: Let $f : A \mapsto B$ be a function. $f$ is injective if and only if for all $X \subseteq A$, $f^{-1}(f(X)) \subseteq X$.  Proof:  $\Rightarrow$ Suppose that $f$ is injective. Let $X \subseteq A$, and let $x \in X$. Since $f$ is injective, $f^{-1}(f(X)) = \{x\} \in X$, so $f^{-1}(f(X)) \subseteq X$.   $\Leftarrow$ Suppose that for all $X \subseteq A$, $f^{-1}(f(X)) \subseteq X$. Let $a_1, a_2 \in A$ and $X = \{a_1\}$. Suppose $f(a_1) = f(a_2)$. If $a_1 \neq a_2$, then $f^{-1}(f(X)) = \{a_1, a_2\} \not \subseteq X$, a contradiction. Thus $a_1 = a_2$, so $f$ is injective. Does Stack Exchange use caching and if so, how? Detailed Bathymetric/Bathymetry contour data (0-200M) Why does Vader live on Mustafar? In Rogue One, we get our first glimpse of Darth Vader's primary residence - a castle on Mustafar.  Given the freedom to choose any planet in the galaxy as their new home, I don't think many people would pick the place where they had three limbs chopped off, fell into a lava flow, and were burned alive, but this appears to be what Vader did.   Why does Vader live on Mustafar of all places? While trying to create a custom business rule using Apex I got the error:  INVALID_ID_FIELD, SaveAsActivity is not allowed with whatId that is not supported as a task whatId.  ...and found out that it was caused by the method setSaveAsActivity on my code, that was like:  msg.setSaveAsActivity(true); // "msg" is a SingleEmailMessage   What am I doing wrong here? Why does input capacity of an opamp increase noise gain? On the image below you can see an inverting amplifier with input capacity C1 and capacity C_F for general stability.     Now my book shows me following frequency plot:  A_n ... Noise-Gain  A_D ... open-loop gain  A_U ... V_out / V_in --> inverting amplifier gain     You can clearly see that C1 is increasing the noise gain at some point. And C_f is stabilizing A_n and A_U.   But why exactly does C1 increase the noise gain exactly? How to translate and rotate the heading of landscaped pages? Objective  How to change the heading of landscaped pages from    to    ?  Minimal Code  \documentclass{book} \usepackage[a5paper,hmargin=3cm,vmargin=5cm]{geometry} \usepackage{lscape,lipsum}  \begin{document} \chapter{One} \lipsum[1]  \section{One One} \lipsum[2]  \newgeometry{hmargin=5cm,vmargin=3cm}  \begin{landscape} \lipsum[3-5] \end{landscape}  \restoregeometry \lipsum[6]  \end{document}   Edit 1 (my real scenario layout)  In my real scenario, the left-right margins should not be occupied by headings. How long to wait after sending an email to a professor before I should assume that I will never receive response? using underscore's “difference” method on arrays of objects Visual Studio "Find" results in "No files were found to look in. Find stopped progress." I am reading George Gamow's book  and a certain assertion Gamow makes seems a little startling considering what I already know of the subject of infinite cardinality.     But the number of all geometrical points, though larger than the number of integer and fractional numbers, is not the largest one known to mathematicians. In fact it was found the variety of all possible curves, including those of the most unusual shapes, has a larger membership than the collection of all geometric points, and thus has to be described by the third number in the infinite sequence. [Gamow, 22]   He later does explicitly say the number of all possible curves is $\aleph_2$. But nowhere else can I find reference to this being true, nor does he provide any sort of reasoning to its validity.  My question is how can you prove the set of all possible curves is of cardinality $\aleph_2$ and not $\aleph_1$ or $\aleph_0$? I'm trying to amass a list of physics books with open-source licenses, like Creative Commons, GPL, etc. The books can be about a particular field in physics or about physics  in general.  What are some freely available great physics books on the Internet? edit: I'm aware that there are tons of freely available lecture notes online. Still, it'd be nice to be able to know the best available free resources around.  As a starter:         Table of contents sorted by field (in alphabetical order): Is it possible to bring built-in lightning components into aura component? I have a form that needs to let the user select 3 out of 5 products, something similar to Order > Add Product (Modal). I was wondering if there was a way to bring that piece into my component (markup) and add some sort of filter that only shows the products I want to show.  What I found so far:  &lt;lightning:listView objectApiName="Products2" listName="productsView" showActionBar="true" enableInlineEdit="true" showRowLevelActions="true"/&gt;   But Product2 is not supported for that component.  also these from browser inspector:  forceMultiAddUsingLVM forceListViewManager   These are data-aura-class attributes when rendered.  I'm looking for directions here. Thanks in advance. I've been having this issue for a while where I come to open the Terminal and I'm met with this:  Login incorrect login: _   I've already deleted the com.apple.terminal.plist to no avail. The really interesting thing is that sometimes it works, maybe 1 in 50 times. I literally have no idea what might be causing it and after searching the web for the better part of half a day it seems everyone else's issues are fixed when they delete the plist file.  How do I sort this out? I've tried running different shells (bash and zsh), but I still get this log in screen.  Also when I use Activity Monitor, I can see there is no shell running just the login. I'm trying to put together a comprehensive regex to validate phone numbers. Ideally it would handle international formats, but it must handle US formats, including the following:   1-234-567-8901 1-234-567-8901 x1234 1-234-567-8901 ext1234 1 (234) 567-8901 1.234.567.8901 1/234/567/8901 12345678901   I'll answer with my current attempt, but I'm hoping somebody has something better and/or more elegant. "going to" vs "will" I know several questions were asked about the difference between "going to" and "will". Based on several answers (see, for instance, ,  and ), I understood that "will" is more spontaneous and "going to" is used with more planned actions.  So, it seems that everything is pretty fine. However, in , Kosmonaut has an answer in which he states: "Let's say that tomorrow you will walk your dog from 7 - 8 AM".  On the one hand, you probably planned to walk your dog long before and thus I should use "Let's say that tomorrow you're going to walk your dog from 7 - 8 am".   On the other hand, since I'm saying "let's say...", I'm deciding right now (thus, unplanned) that you will walk your dog. So, even though in this hypothetical situation you made a plan, I'm in a more spontaneous mood deciding right now that that's what you will do tomorrow, and, thus, I should use "will".  Which one (if any) of the above explanations is right? Can't find the reason why root directory usage is so large A friend wants to use my account for a wire transfer. Is this a scam or is it legitimate? I have a friend since July online and Exxon owe him for a balance on a 2014 contract off the shores of Liverpool. He is presently in the Gulf of Mexico completing a contract that last for one year. During that year he cannot get off the boat there fore he cannot receive the money.  Exxon has notified him that his check has been deposited in Samba Bank in London. If he doesn’t receive his money within two weeks it goes back to Exxon and he said that there I not telling nohow long before he will receive the money again. He said that with him being off shore that he needs me to be his beneficiary to receive the money for him. He wants me to keep the money in my account and when he gets off the boat in 6 weeks he is relocating to where I live.  I am to buy a house before he gets here and then he wants us to start a business together. He talked with me for quite a while before he told me how much he makes. He knows I do not have any money to mention. I have stock in a formal shop but not any money.  He said if this money had not come in when it did he would have had to postpone his plan until he gets paid what Shell Oil owes him for this contract that he will finish October 15th. He said he had given enough of his life to the gas and oil industry and is not going to sign another contract.  What do you think about the safety of this?