I'm getting swamped with outbound udp requests and it's blocking my internet connection.  While I figure out what's going on I'd like to block all outbound and inbound udp. I'm connecting via pppoe dial up but want to block on all ports and all connections. Is there a way to do this that won't interrupt my pppoe connection?  I've tried updating iptables but this seems to only block one port at a time if I understand correctly.  Though I have rules in my firewall to block the ports it seems to be too late.   For newbies like me it is difficult to get the pieces together and I couldn't find the answer on searching because didn't know to search for iptables and that doesn't cover the udp component. I have my question answered by think this should remain open for others as I believe it might be helpful.
Is there a "best practice" or standard to make a few iptables rules permanent? I mean: automatically applied upon a system reboot?  I am using a VPS with Ubuntu Server 10.04 LTS (Lucid Lynx).  Thank you.  BIG EDIT: I don't want ANY rule to be persisted (like iptables-persistent package does). I want only my own specific set to be reloaded... if other rules are eventually added by running iptables, these should be discarded...
Square of a function with an essential singularity Let $a$ be a point on the complex plane such that the function $f$ has an essential singularity. I am trying to prove that the square of that function also has an essential singularity.  I suppose that it does not have an essential singularity. Then $\exists ;k$ such that $(z-z_0)^{2k}f^2(z)$ differentiable. Then if I could take the square root and preserve the differentiability I would have finised. Can I do that? Why does an integral change signs when flipping the boundaries? Let us define a very simple integral:   $f(x) = \int_{a}^{b}{x}$    for $a,b\ge 0$.  Why do we have the identity $\int_{a}^{b}{x} = -\int_{b}^{a}{x}$?  I drew the graphs and thought about it but to me integration, at least in two-dimensions, is just taking the area underneath a curve so why does it matter which direction you take the sum? For a presentation with Beamer, I would like to have a slide where a long list of formulas (maybe mixed with text) scrolls automatically within a certain part of the slide. This should look like e.g. closing credits in movies.   I have tried the idea from  based on animateinline from the , but whenever I use environments like \begin{equation} ... \end{equation} or commands like \textcolor{red}{...} I get an error:  TeX capacity exceeded, sorry [main memory size=3000000]. \end{frame}   Ideally, the formulas/the text should be given within the document itself, but if a solution with an external PDF works fine, I'll take it!  Any ideas how that might work? How is Anti Aliasing Implemented in Ray Tracing? After reading a few articles online I can confidently say I am clueless on how Anti-Aliasing works when using Ray Tracing.  All I understand is that A Single Pixel/Ray is split into 4 sub-pixels and 4 rays rather than 1.  Could somebody please explain how this is done (preferably with code)? Let $f$ be an entire function and $L$ a line in $\mathbb{C}$ such that $f(\mathbb{C})\cap L=\emptyset$. Show that $f$ is constant function.  If $f$ is not constant  then $f(\mathbb{C})$ is dense set in $\mathbb{C}$, but how can I use that line does not intersect the image set? How to insert code with accents with listings? I'm trying to insert source code in LaTeX with using listings, but my code has accents and pdflatex gives me this error:  Unicode char \u8:�\expandafter not set up for use with LaTeX.   This is a code the reproduces the error.  example.tex  \documentclass{article} \usepackage{listings} \usepackage[utf8]{inputenc} \usepackage[spanish]{babel}  \begin{document}  \lstinputlisting[language=C++]{code.cpp}  \end{document}   code.cpp  // Código con una tilde   What can I do to generate the PDF correctly? How do I automatically decrypt an encrypted filesystem on the next reboot? Goal  I am looking for non interactive way to decrypt a root file partition and a swap partition encrypted with LUKS the next time the system reboots. As well as this, I need a way to undo it after the reboot so that it after one more reboot will require the password again (or even a new password).  The system uses LVM.  I don't want to have to type the password on the system, or use a different system to unlock it, it has to unlock itself that one time.  I have the password it is encrypted with, and would be willing to save it in cleartext on the harddrive. I am not concerned with security at this step.  Background  I have a flow for deploying Ubuntu that is based on an Ubuntu server installation with a custom preseed and kickstart file, kickstart installs a service that run after the first reboot (and only the first reboot) and then reboots again. I am trying to implement LUKS disc encryption in this flow, but I need it to remain non interactive, so it has to be able to restart the first time without a password.  The password set during installation is temporary and will be changed by the service that runs after the first reboot, so the first password can be stored in clear text.  Things I have looked into before posting this question  I have done my fair bit of Googling to try and figure this one out, and most of what I find point towards a solution that swaps out the initramfs file.  I have found multiple resources that explain how to use this to allow for remote unlocking the system, but I need to do it without interaction. Here is one such resource:   The closest thing to a solution I think I have found, is this resource which is supposedly a way of accomplishing what I want for a VPS solution, but it is just a bunch of commands with no explanation, and I don't know how to adapt it:   I also found this resource for ArchLinux , and I have tried adding the kernel parameters, but I have not had any luck with that either. I don't know if it is because LUKS does not support these kernel parameters. What is the difference between sector and cluster? I have gone through wikipedia and other sites and here's the information I have obtained.  Sector: Smallest Addressable Unit (mostly 512 bytes) Cluster: Smallest Allocation Unit (equals to 1 or more sectors and the number of clusters depends on the file system).  Let's say in the below example:  sector =512 bytes and a cluster =8 sectors=4096 bytes. Now, I am having a hard time figuring out, when I am trying to create a file what does the file system do? Does it consider 4096 bytes as the smallest write/read unit or 512 bytes?  If the answer is 4096 bytes: When the manufacturer of the disk drives has provided 512 bytes as the smallest addressable unit, why does the file system consider cluster as the smallest unit? I mean, what are the advantages in doing so? Six simple tips to get Stack Overflow reputation fast A mod-only section of the help center Copy & Pasting from Photoshop to Illustrator loses transparency I often run into this issue. I'm creating a file in Photoshop with masked layers etc. I want to make the final output available for some mock-ups in Illustrator, so I rasterize the layers and marquee select the entire area, copy and move to Illustrator.  Pasting the area in Illustrator flattens all transparencies, which is quite annoying. I'm left with my object and a flat white background.  Is there a reason for this? What is the maximum or minimum tire width I can fit on my bicycle Prove $e^{x+y}=e^{x}e^{y}$ by using Exponential Series Intuitively, $\lim\limits_{t\to -\infty}te^t=0$, since $e^t\to 0$ much faster than $t\to -\infty$.   Is there a way to more rigorously compute this? Writing it as $e^t/(1/t)$ seems resistant to l'Hopital's rule. how long does the care take to reach the last pole algebra word problem There are 20 poles with a constant distance between each pole. A car takes 22 seconds to reach the 12th pole starting from the first pole, with a constant speed between each pole. how many seconds will it take to reach the last pole?   Is the answer 36 seconds?   since $\frac{22} {12}  = 1.83 $  $1.83 \times 20 = 36.67 $ $X_n\leq Y_n$ implies $\liminf X_n \leq \liminf Y_n$ and $\limsup X_n \leq \limsup Y_n$ Can anyone prove this question? I tried but I didn't get any I idea, so I hope someone can solve it.     Let $X_n\leq Y_n$ for each $n\in \Bbb N$. Show that $\liminf X_n \leq \liminf Y_n$ and $\limsup X_n \leq \limsup Y_n$.   Please prove this question - thanks.  The definition I have:     Let $X_n$ be a sequence in real number and let $$E=\{x\in \Bbb R^\sharp:(X_{n_k}) \rightarrow x \text{ for some subsequence }(X_{n_k})\text{ of }(X_n)\}$$ for all $n \in \Bbb N$ and $k$ from $1$ to $\infty$. Then by definition $\lim\sup X_n = \sup E$ and $\lim\inf X_n = \inf E$. There's a story my grandpa use to tell me when I was younger, about the sole survivor of of an attack on a mining vessel in space. The man lives in space for months/years, ignored by the company he worked for and never rescued. Then when he thinks he is being rescued, it's actually another set of raiders who attack him and kidnap him.  He then wakes up in captivity in some sort of prison inside of an asteroid, and has a word tattooed on his forehead. My grandpa called him Ronin (that's what the tattoo on his forehead said) but I don't know what the character's real name is. Anyways, he learns that he has the ability to teleport after having a brush with death and decides to make his way back to Earth so that he can exact revenge on the mining company who abandoned him and left him floating to die.  Does anyone know what this story or book may be? My grandpa told it to me when I was little, he said that he got it from a book he use to love reading when he was younger. I'm assuming the book is very old (possibly pre 1940's as he was born in the 20s). I can't ask him as he is no longer alive. I'm also unsure as to whether or not all the details in the story he told me, are the same as in the original. $A$ is normal and nilpotent, show $A=0$ Given a matrix $A \in R^{n \times n}$ which is normal ($AA^H=A^HA$ where $A^H$ is hermitian of $A$) and nilpotent ($A^k=0$ for some $k$). Now we need to show that $A=0$. (This is essentially exercise 5(b) in sec. 80 on p.162 of Paul R. Halmos' Finite-Dimensional Vector Spaces.) I tried to show in the following way, we know that, $AA^H=A^HA$ pre-multiply by $A^{k-1}\implies A^kA^H=A^{k-1}A^HA$ Now, we have $0 = A^{k-1}A^HA$, since $A$ nilpotent. I am not sure how to proceed from here to show $A=0$. Can someone help me in this problem? We have set up GA on several websites to gather information about traffic to the site. We know about the organic keywords that are displayed under the Acquisition section of the traffic report. But we have been asked to find a way to display "not provided" keywords typed in by the end user in our Google Analytics report.  Is it possible to accomplish this? Interpreting coefficient in a linear regression model with categorical variables I will give my examples with R calls. First a simple example of a linear regression with a dependent variable 'lifespan', and two continuous explanatory variables.  data.frame(height=runif(4000,160,200))-&gt;human.life human.life$weight=runif(4000,50,120) human.life$lifespan=sample(45:90,4000,replace=TRUE) summary(lm(lifespan~1+height+weight,data=human.life))  Call: lm(formula = lifespan ~ 1 + height + weight, data = human.life)  Residuals: Min       1Q   Median       3Q      Max  -23.0257 -11.9124  -0.0565  11.3755  23.8591   Coefficients:              Estimate Std. Error t value Pr(&gt;|t|)     (Intercept) 63.635709   3.486426  18.252   &lt;2e-16 *** height       0.007485   0.018665   0.401   0.6884     weight       0.024544   0.010428   2.354   0.0186 *   --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1   Residual standard error: 13.41 on 3997 degrees of freedom Multiple R-squared: 0.001425,   Adjusted R-squared: 0.0009257  F-statistic: 2.853 on 2 and 3997 DF,  p-value: 0.05781   In order to find the estimate of 'lifespan' when the value of 'weight' is 1, I add (Intercept)+height=63.64319  Now what if I have a similar data frame, but one where one of the explanatory variables is categorical?  data.frame(animal=rep(c("dog","fox","pig","wolf"),1000))-&gt;animal.life animal.life$weight=runif(4000,8,50) animal.life$lifespan=sample(1:10,replace=TRUE) summary(lm(lifespan~1+animal+weight,data=animal.life))  Call: lm(formula = lifespan ~ 1 + animal + weight, data = animal.life)  Residuals: Min      1Q  Median      3Q     Max  -4.7677 -2.7796 -0.1025  3.1972  4.3691   Coefficients:             Estimate Std. Error t value Pr(&gt;|t|)     (Intercept) 5.565556   0.145851  38.159  &lt; 2e-16 *** animalfox   0.806634   0.131198   6.148  8.6e-10 *** animalpig   0.010635   0.131259   0.081   0.9354     animalwolf  0.806650   0.131198   6.148  8.6e-10 *** weight      0.007946   0.003815   2.083   0.0373 *   --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1   Residual standard error: 2.933 on 3995 degrees of freedom Multiple R-squared: 0.01933,    Adjusted R-squared: 0.01835  F-statistic: 19.69 on 4 and 3995 DF,  p-value: 4.625e-16   In this case, to find the estimate of 'lifespan' when the value of 'weight' is 1, should I add each of the coefficients for 'animal' to the intercept: (Intercept)+animalfox+animalpig+animalwolf? Or what is the proper way to do this?  Thanks Sverre