First of all, I know that this question covers a similar ground as  but the topic is one year old and pertaining to the last year's World IPv6 Day.  Today is June 6, 2012, , so I ask whether SE has made any plans to enable IPv6 on their servers in this year. Many large content providers such as Google,  Facebook and perhaps most importantly Akamai have already made the switch so it is possible to access a somewhat large portion of Internet via IPv6 only.  Since IPv4 depletion is becoming more and more a severe issue we can expect that ISPs that won't be able to get new IPv4 allocations will start connecting their clients to IPv6-only connections or resort to CGNs which bring about many other problems such as identification of clients behind those CGNs and performance issues.  I think many users will appreciate IPv6 connectivity to SE and I think it is not a large problem from a technical viewpoint. A reverse IPv6 proxy will probably do just fine for the time being (similar to what Amazon AWS  to provide IPv6 connectivity to their clients while they are upgrading the platform to the full-fledged IPv6 connectivity)  EDIT: Bump, because it's 2014 and IPv6 is still not there.
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According to my IPv6 tunnelbroker  the world will end in approximately 712 days when we finally run out of IPv4 addresses.  Would it be possible to enable IPv6 access to the Stack Exchange family of websites?
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Java applets are soon to be killed off forever.  I understand why we shouldn't make new ones.  But what will happen to old ones?  There are still Java applets that people may use, and there's no guarantee that anyone will be willing or able to port them to JavaScript.  For example,  has a lot of Java applets that explain and visualize certain digital audio concepts.  Another course I'm taking uses a lot of Java applets to visualize computational geometry ideas.  When Firefox drops NPAPI support, that's it, we've cut off this great reference material to all but those willing to jump through arcane technological hoops.  The following possible solutions don't always fit the bill:   Just use FireFox   Port it or rewrite it  May not be open source, or it may not be practical to do so (e.g. lack of domain knowledge). Ask the original author to do it  They may have stopped supporting it years ago.  Doesn't make it any less effective at, say, tracing out the steps for Delaunay triangulations. Find an alternative  If none exist, we're back to the second option.  If the only ones that do exist aren't browser-based, all bets are off for convenience (which is the whole point of browser apps).   Is there currently (or will there be within a year) a convenient, cross-platform way to run existing Java applets once all the major Web browsers drop NPAPI support?  Note that:   Actually so in-browser isn't critical, but it should still be cross-platform.  Ideally I wouldn't have to download extra software (after all, I already do have a JVM installed). No, I'm not suggesting we re-open the security holes that Chrome and Firefox are trying to close. If there are alternative Web browsers out there designed specifically for legacy Java applet support (or at least with no plans to drop existing NPAPI support), I would be okay with that.
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This is a  about IPv6 Subnetting.      Related:               I know a lot about , and as I prepare to (deploy|work on) an IPv6 network I need to know how much of this knowledge is transferable and what I still need to learn. IPv6 seems at first glance to be much more complex than IPv4. So I would like to know:   IPv6 is 128 bits, so why is /64 the smallest recommended subnet for hosts? Related to this:   Why is it recommended to use /127 for point to point links between routers, and why was it recommended against in the past? Should I change existing router links to use /127? Why would virtual machines be provisioned with less than a /64 worth of addresses? Are there other situations in which I would use a subnet smaller than /64?  Can I map directly from IPv4 subnets to IPv6 subnets? For instance, does an IPv4 /24 correspond directly to an IPv6 /56 or /120? My interfaces have several IPv6 addresses. Must the subnet be the same for all of them? Why do I sometimes see a % rather than a / in an IPv6 address and what does it mean? Am I wasting too many subnets? Aren't we just going to run out again? In what other major ways is IPv6 subnetting different from IPv4 subnetting?
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Ubuntu provides some good information on how to enable UFW and on how to enable IPv6 with miredo:       But what is missing is information on how to properly configure UFW to let Miredo work, as as soon as I enable UFW IPv6 stops working:  $ ufw disable $ ping6 ipv6.google.com PING ipv6.google.com(2a00:1450:8004::93) 56 data bytes 64 bytes from 2a00:1450:8004::93: icmp_seq=1 ttl=56 time=1886 ms $ ufw enable $ ping6 ipv6.google.com PING ipv6.google.com(2a00:1450:8004::6a) 56 data bytes ping: sendmsg: Operation not permitted   So how do I properly configure both Miredo and UFW together that basic IPv6 is working, but with all other incoming traffic being blocked?
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I am attempting to set up a web server (nginx) that needs access to the internet while also being hooked up to an ELB but I am having trouble getting this solution working.  Details:   3 public subnets   a b c  3 private subnets   a b c  1 ELB   This has the three public subnets included in its default pool  1 NAT instance in public subnet   The various guides I have found useful for getting the public subnets hooked up to the ELB by pointing the subnets to the IGW.  These set ups do not take in to consideration the need for internet access.  When I change the route table for the single NIC from the IGW to the nat instance I get internet access but I lose the ability to connect to the ELB and visa versa, when I update the route table to use the IGW I lose the ability to connect to the internet.  I can allocate an EIP and give it access that way but was hoping to avoid exposing this server the internet via a public address if possible.  What I am thinking is that I can either 1) add a second NIC to the web servers that need internet access so they have a leg out via a NAT instance and also have a leg in the public subnet to connect to the load balancer or 2) I can use the nat instance as the gateway for my network.  Has anybody set something similar to this up?
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I am not looking for a workaround or a hack.  I am just confused.  14.04.1 has been released now for a week, and one of my machines which is on 12.04, and another one which is on 14.04 both don't have the upgrade options.  I see there is a 14.04.5 release on august 7th but I am not sure what a candence event is.    It is hard to believe that it is not an issue that is going to be resolved otherwise I would hope this would be posted on the Ubuntu blog.  I cant be the only one on the last LTS waiting for it to update so I can finally go to the latest kernel and properly use my core i7 graphics.
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I came across something rather interesting today. I was browsing Area 51 on Chrome when I happened to click on . To this, I was greeted with a prompt asking:    As , and fully expecting a crash, I clicked on SE. However, that didnt happen.     Now, since Area 51 Meta is working correctly as far as Q&amp;A is concerned, I think it should be added to the All Sites list and if at all possible, made directly browsable from within the app.
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This is a  about securing public DNS resolvers   Open DNS servers seem pretty neat and convenient, as they provide IP addresses that we can use consistently across our company regardless of where they are located. Google and OpenDNS provide this functionality, but I'm not sure that I want these companies to have access to our DNS queries.  I want to set up something like this for use by our company, but I hear a lot about this being dangerous practice (particularly in regards to ) and I want to make sure that we do this right. What things do I need to keep in mind when building this type of environment?
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Upgrading my Ubuntu 14.04 LTS to 16.04 then 18.04 LTS left LTSP unable to boot clients. I am using the traditional 2 NIC structure on 1404, with thin clients on a physically separate subnet, and their system in chroot. It uses isc-dhcp-server and tftpd-hpa.  Trying to debug my upgraded system (including switching to dnsmasq) I came across bugs which only seem to be fixed in versions of packages later than those in the bionic repos, with no backports, so I gave up on the upgrade route.  So is there a currently reliable way of installing LTSP on 1804?
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How does one disable IPv6 completely (for all interfaces, resp. for the whole machine?  Keep in mind, I don't want any kind of GUI solution.    OS in question:   Linux Mint 18.x Cinnamon 64-bit GNU/Linux Debian 9.x Cinnamon 64-bit
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For about 2 weeks, multiple people (around 10 that I know of) in our company are having trouble accessing Stack Overflow; independently of the browser, and on Linux as well as Windows. The symptom is that assets loaded from cdn.sstatic.net keep waiting forever or until they time out.   On my machine the status is that at some point those requests time out and a version of the page without any images or CSS appears.  For some Windows users reboots help, for others it doesn't.   Meta Stack Overflow (now Meta Stack Exchange) always loaded for me.  A workaround for my machine was to disable IPv6 temporarily on Linux with the command echo 1 | sudo tee /proc/sys/net/ipv6/conf/all/disable_ipv6.  Note that no other site (that I visit) has been affected like this.  Update 2013-08-12: our network guy did some checking and insists the problem lies with Cloudflare. We seem to have issues when trying to connect to them with IPv6. We can't go around and disable our IPv6 Support since we need it for our internal infrastructure. We employ the following workaround (sadly only works with Firefox):   Go to about:config find the configuration key called network.dns.ipv4OnlyDomains Set it to the following list of domains (or add them if you already have something in this key): cdn.sstatic.net,www.cloudflare.net,cdn-careers.sstatic.net
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I went to stackexchange.com and clicked on SO.  After a few minutes I got a message saying "We have detected too many requests from this IP.  If this is an error contact us."  That was the second SE page I tried to visit.  Second only to SE.com  I moved to another machine and it's working now.  The first machine usually works, I don't know if a got assigned a blacklisted IP or what.  Anyone know what's going on?  EDIT: I would really rather not post my IP on the web, but if a diamond or dev asks I'll email it.  EDIT 2: I looked at badp's dupe suggestion and can verify that I have no scripts frequently calling SO.
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We are trying to configure our Cisco 5505, and it has been done through ASDM.  There is one big problem that we're not able to solve, and that's when you go from inside to outside and back in again.   Example, we have a server "inside" and we want to be able to reach this server with the same adress if we're on the inside or if we're on the outside.   The problem is adding a rule that will allow traffic from inside to outside and then back in again.
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The major browsers are moving beyond SSL3.0 and TLS1.0 . The PCI Security Council has declared an end-of-life date for these protocols to be considered sufficiently strong encryption.   We need to move away from these protocols, to use newer and stronger ones. On Windows servers, you can very easily disable these old protocols, and instead offer only TLS1.1 or greater.  However, as noted , Microsoft SQL Server 2008 R2 and SQL Server 2012 (Standard, at least) both will not start if those lower protocols are disabled.  However, there are a growing number of versions of MS SQL Server.  There are SQL Server Standard, Business Intelligence, Enterprise, Express, Web, and Compact editions.  And of course there is SQL Server 2008, 2012, 2014, and (in pre-release) 2016.  Which of these editions support or will support the use of only TLS1.1 or greater protocols?
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one of my servers (Debian 5.0.6) has two public ip-address on the same interface. This used to work well for months but suddenly it is using "the wrong" ip addresses for outgoing connections. This is a problem because the reverse lookup will not match and emails therefore get spam points.  eth0      Link encap:Ethernet  Hardware Adresse 00:1b:21:14:8e:9c             inet Adresse:81.169.180.51  Bcast:81.169.180.51  Maske:255.255.255.255           inet6-Adresse: fe80::21b:21ff:fe14:8e9c/64 Gültigkeitsbereich:Verbindung  eth0:0    Link encap:Ethernet  Hardware Adresse 00:1b:21:14:8e:9c             inet Adresse:85.214.157.120  Bcast:85.214.157.120  Maske:255.255.255.255   Kernel-IP-Routentabelle Destination     Router          Genmask         Flags Metric Ref    Use Iface 81.169.180.1    0.0.0.0         255.255.255.255 UH    0      0        0 eth0 0.0.0.0         81.169.180.1    0.0.0.0         UG    0      0        0 eth0   Currently it is using 85.214.157.120 for outbound connections. How do I get it to use 81.169.180.51?  Edit: The netmask of 255.255.255.255 is consistent with both documentation and DHCP response of the hosting company. Calling /etc/init.d/networking restart multiple times will eventually end up with the correct ip-address for outbount connections. But that is obviously not a stable solution. /Edit  Edit 2: To make sure that the host route is not related to my issue, I setup a local test network:  eth0      inet Adresse:192.168.0.2  Bcast:192.168.0.255  Maske:255.255.255.0 eth0:0    inet Adresse:192.168.0.3  Bcast:192.168.0.255  Maske:255.255.255.0  192.168.0.0    0.0.0.0         255.255.255.0   U     0      0        0 eth0 0.0.0.0        192.168.0.1     0.0.0.0         UG    0      0        0 eth0   If anyone has an idea how to make sure that source ip-address 192.168.0.2 is used on outbound tcp connections, I'd be thankful. /Edit 2
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I've grown quite fond of HTTP reverse proxies in our development environment and found the DNS based virtual host reverse proxy quite useful. Having only one port (and the standard one) open on the firewall makes it much easier for management.  I'd like to find something similar to do SSH connections but haven't had much luck. I'd prefer not to simply use SSH tunneling since that requires opening port ranges other than the standard. Is there anything out there that can do this?  Could HAProxy do this?
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We have dozens of virtual machines in several data centers around the world. When upgrading an Ubuntu VM from 14 to 16 (as a step toward upgrading them to Ubuntu 18), the network interface names change. I am aware of this, and I know why they change, so that is not my question. My question is where does the number (the 33 in ens33, the 192 in ens192, etc.) come from? I have read many StackExchange questions and answers about what to do to get the server working: that is not the problem. What I want to know is how to predict what the ens### will be before the server is upgraded to Ubuntu 16. I have looked at lshw and lspci, and I can't see any reason why these numbers are chosen.  Please: where does the 192 (or 33, or anything else) come from?