I suspect iptables to refuse some connection attempts I do on some ports. How to view the log of connections refused by iptables?  I use iptables on Kubuntu 14.04 LTS x64.  sudo iptables -v -x -n -L outputs:  francky@francky-Aurora-R4:~$ sudo iptables -v -x -n -L Chain INPUT (policy ACCEPT 1735891 packets, 225230318 bytes)     pkts      bytes target     prot opt in     out     source               destination  6368899 10355529368 fail2ban-ssh  tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            multiport dports 22  Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)     pkts      bytes target     prot opt in     out     source               destination  Chain OUTPUT (policy ACCEPT 3860995 packets, 5648955269 bytes)     pkts      bytes target     prot opt in     out     source               destination  Chain fail2ban-ssh (1 references)     pkts      bytes target     prot opt in     out     source               destination  6362396 10355135821 RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0
I have this rule in my iptables:  iptables -A INPUT -s 192.168.11.0/24 -j LOG   My question is:  Where is the iptables log file, and how can I change that?
Writing letters of recommendation for more than one student to the same department Suppose multiple students have asked me for letters of recommendation to the same graduate department in the US. Am I expected to explicitly compare the students to one another? Am I supposed to do this in both letters (assuming they haven't been submitted yet)? Do I need to explicitly state a preference for one over the other, or can I just get away with listing relative strengths and weaknesses (for instance, "X is stronger academically, but Y has more research experience and is a stronger programmer")? Some Git commands take commit ranges and one valid syntax is to separate two commit names with two dots .., and another syntax uses three dots ....  What are the differences between the two? Having Overfull and underfull box warnings. Please help out as there are many matrices and equations Correlating filename with package Say, I'm given a filename like libasound.so.2. Is there a way to query the package manager to correlate the filename with its corresponding package?  I'm interested to get answers for any package manager, but my primary focus is on apt and yum. How to make Outlook 2010 minimize when I try to close it? When clicking the X button or ALT+F4, how can I get Outlook to minimze to the tray instead of close?  Several programs have this behavior, and it's annoying that Outlook behaves different... How to solve the diffencial equation for power series $(1+x²)y'' - 6xy=0$ in $x_{0}=0$ I have tried for the power series but when suppose the solution is $y(x)=\sum _{n=0}^\infty a_nx^n$ appeared sums dependents of $a_n$,  $a_{n+2}$ and $a_{n-1}$ and this is not possible. Is Lambert Academic Publishing a reputable company? I was contacted by the Acquisition editor of Lambert Academic Publishing (LAP) to publish my bachelor's thesis as a printed book. Is LAP any good? I have no idea about it; I have just heard that it's a freelance publishing house. Book series my dad told me about. It involves space travel, clones, and an indigenous people with kangaroo tails My dad read a book series that he recommended to me last year. Now that I am ready to start it, neither of us can recall the title. He said there were several in the series but he can't recall how many.   The book is about traveling to a new planet, presumably with the goal of colonizing it. The crew are clones who have no memory. I think the goal was for the older original versions of the clones to transfer their consciousness into the clone bodies to be able to live on the new planet but something goes wrong.   There is an indigenous species on the planet who are humanoid but have kangaroo like tails.   The clone crew has markings on them that they don't understand until late. Apparently they are markings to indicate status or role on the new world. The person who they voted as there leader, it turns out, is marked as a servant or slave class. In what order should one apply max HP reduction and damage? A character at 10/26 HP is hit by a Wraith and fails the Constitution saving throw. They take 21 damage and their maximum HP is reduced to 5.  Are they unconscious because the 11 excess damage is less than 26 or dead because it's greater than 5? What is the greatest integer that divides $p^4-1$ for every prime number $p$ greater than $5$? What is the greatest integer that divides $p^4-1$ for every prime number $p &gt; 5$?  This was on a practice math GRE so it's probably really easy. Why would someone buy a way out-of-the-money call option that's expiring soon? I swing trade equity options every once in a while for fun. This morning I witnessed something I do not understand at all.  In the attached photo, why would someone purchase 6 contracts for .05 at $76.  I just can't wrap my head around this!    Scenario:   Underlying Asset: RY.TSX  Current Price: $71.70 Days to expiry: 4 Days     EDIT: It happened again the next day with 74, see new table with headers as per request:   My only reason for asking is because RY.TSX is the Royal Bank of Canada, this stock will not move multiple dollars in 3 days(expiry in this scenario).  Why buy 10 @ 74 for .04 each instead of just buying 10 @73 for .04 which would have gone through.  If you do the math(excluding commissions): .04 * 100(shares in a contract) * 10 contracts = $40 Stock moves to 74 and they are in the money lets say for .20 .20*100*10 = $200  I just don't see the reward as 99% of the time you will lose this wager, it is just not worth it even if it does happen once in a blue moon.  I can think of much better things to do with $40.  For the skeptics another screen shot to actually confirm this order: App question timer shouldn't kick in until submission I attempted to ask a question using the iOS app, but it was rejected due to lack of a required tag. On adding the tag I found that I wasn't permitted to submit the question for another 60 seconds, even though this wasn't a new question.  Is this timer intentional, or should it not kick in for edits of questions not actually accepted by the site? Do positive semidefinite matrices have to be symmetric? Can you have a non-symmetric matrix that is positive definite? I can't seem to figure out why you wouldn't be able to have such a matrix, but all my notes specify positive definite matrices as "symmetric $n \times n$ matrices."  Can anyone help me with an example of a non-symmetric positive definite matrix, or some insight into a proof for why it would need to be symmetric should that be the case? Thanks! PATH variable resets with reboot Just as the title indicates my PATH variable resets after every reboot. I read that I have to edit my bashrc file's PATH variable, but I don't have anything there that suggests anything related to the PATH variable. How are the age restrictions followed by ICC for under 19 cricket tournaments? I have some doubts under this topic,   Can a player aged 19 play under 19 international cricket match? (Since 19 is not under 19) Consider a player having birthday during the series/tournament. How the age will be calculated for him? Why do games run slow on CPU Maybe my question sounds naive because I'm not a game developer but I dont see objective reasons for this. An average cpu is in times more powerful than an average gpu like a few graphics cards in one. The most repeated reasons in internet:  the GPU isn't as busy as the CPU  If the gpu renders the screen how it can not be busy The modern cpus are powerful enough. They are not busy most of time. For example my cpu's usage is 3%.  many GPU's are designed to process graphics commands in parallel, CPU single threads them  What bothers the games to run a few parallel processes even on one cpu core? In my opinion its not correct to tell that the gpu is better if games never use 100% of the cpu's capacity. To be specific they dont use even 50%.  To clarify my question based on responses in the comments:  Did you mean to ask &quot;Why do games render more slowly on the CPU?&quot;  Yes I mean why the cpu cant do the whole work for games when it is underloaded and especially if it does the largest part of work in any case.  You can not compare GPUs and CPUs directly, because they do different things.  What bothers them to do the same things?  The CPU isn't as well suited to performing rendering calculations  I dont understand what &quot;suited&quot; means. And why the cpu is not suitable for primitive tasks aka paint roller.  adding additional parallel processes doesn't improve performance  Then why do you produce multicore graphics cards and multicore central processing units? Just give various parts of one task to a few processes if one process is slow and 100% of the capacity is not used. What bothers to emulate the gpu? Its also unclear for me why when you play without a separate graphics module the games see only one cpu core when you play with the gpu they see and use all the cpu cores. May be some magic. CSS bug with printing site pages (now with 100% more suggested fix included!) Why do my xmodmap binds involving AltGr only work on some keys? I want to remap my AltGR+Right_Windows but I can't figure out how. No matter what I try, pressing the right windows key emits the name keysym when right alt is pressed or not.  These are the contents of the xmodmap file I am testing right now. In my keyboard, 38 is the keycode for "a", 48 is the keycode for aportrophe/doublequote and 134 is the keycode for the right windows key.  keycode  38 = 1 2 3 4 5 6 7 8 keycode  48 = 1 2 3 4 5 6 7 8 keycode 134 = 1 2 3 4 5 6 7 8   When I press Right_Alt+apostrophe, it outputs 5 but Right_Alt+a and Right_Alt+Right_Windows give 1 (both when right alt is pressed and when it isn't) which is not what I wanted.  My current keyboard layout is us(alt-intl) and the right alt is apparently set up to act as AltGr / Iso_Level3_Shift. The output of xmodmap -pm is the following:  xmodmap:  up to 4 keys per modifier, (keycodes in parentheses):  shift       Shift_L (0x32),  Shift_R (0x3e) lock        Caps_Lock (0x42) control     Control_L (0x25),  Control_R (0x69) mod1        Alt_L (0x40),  Meta_L (0xcd) mod2        Num_Lock (0x4d) mod3       mod4        Super_L (0x85),  Super_R (0x86),  Super_L (0xce),  Hyper_L (0xcf) mod5        ISO_Level3_Shift (0x5c),  Mode_switch (0xcb) We all know how important proper attribution of ideas is. At the same time, certain things have become basic enough that citing the paper where they were first discussed is overkill: to give an extreme example, if you need to do some differentiation in your math/physics paper, you don't need to go and cite Newton and Leibniz. Now, on occasion students ask me how one can determine if a piece of knowledge is common enough that they can forgo a citation. The rule of thumb I give them is:     If it is something that is explained in a standard first-year undergrad textbook, then anybody who is going to read your papers knows about it and you don't need to provide a citation.   [Here I want to emphasize that I give this to them as a rule of thumb, and I always tell them to ignore it and provide the relevant citation if they think it is necessary to do so in a specific case]  Are there better or alternative ways of drawing the line? My new laptop came preinstalled with Windows 8. Naively, as I am, I just formatted the harddrive and installed fine old Ubuntu. Now I want to install Windows 8 for dual boot again, but I have no DVD and do download the ISO one needs a product key. That key is not on the back of the laptop anymore but somewhere on the mainboard.  Is there any way to recover the product key from the mainboard using Ubuntu?