Posts

gns3v2

GNS3 Version 2 Released! For the uninitiated, GNS3 is an OpenSource, cross-platform network virtualization software, that’s “ used by hundreds of thousands of network engineers worldwide to emulate, configure, test and troubleshoot virtual and real networks. GNS3 allows you to run a small topology consisting of only a few devices on your laptop, to those that have many devices hosted on multiple servers or even hosted in the cloud. “ Ever since the crowd-funding campaign a couple of years ago, the project has benefited from a surge in development, culminating in the latest release announced today. By the way, there’s a GNS3 Academy now, bringing a more democratized approach to training through the use of OpenSource software and affordable prices.  Hopefully, this will do for Networking courses and labs what Udemy , edX , and others have done for other technology-related fields.  Unfortunately, the proprietary hardware and software of industry giants like Cisco or VMWa
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EFF Announces Voting Registration Service

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The Electronic Frontier Foundation ( EFF ) has announced a Beta version of their ongoing project to facilitate voter registration for United States elections.  The server allows the user to text the service, HelloVote , in order to register. There is another service provided by VotePlz.org that allows citizens to: Not sure if you’re registered? No problem! We’ll check if you’re registered to vote at your current home address. Don’t have time to vote in person? You can vote by mail instead—it’s even easier! Want to vote in person? We’ll show you where your nearest polling station is and help you get there. Don’t have a stamp or a printer? That’s all right! We can mail you a form, or print a form with pre-paid postage.
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Apache Webserver, PHP, and Software Collections on RHEL7

The relatively short lifespan of PHP versions does not bode well with Extended Release Operating Systems like Red Hat Enterprise Linux and CentOS. The longevity of the OS is, perhaps, one of the most attractive features for server owners and Administrators. However, as with most things in life, there's always a trade-off. Extended Release Operating Systems provide a long "shelf life" and ongoing support and development for the most important part of a server. It's not surprising then that "bleeding edge" software isn't readily available in the default software repositories. This creates a dilemma in the days of DevOps and increasing Internet penetration. Software Collections have made this type of scenario less problematic. Software Collections provides a repository for more recent, development versions of software that are always separated from the system-wide software installations of a server. This allows us, for example, to run differe
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Resource Load Tips and Tricks

Redirect dynamic page to static page if resource issues arise from high traffic to a single Webpage sar -q top -c netstat -antp lsof -itcp lsof -i :80 When you see the PID that is connecting to a remote port 80 rather than accepting a connection to local port 80, use lsof -p on that pid number to find the working directory of it. Security Check if we support insecure SSLv2: openssl s_client -connect 127.0.0.1:443 -ssl2       Check for outbound connections to remote port 80 netstat -atnp |awk '$5 ~ /80/ {print $0}'   The script above this line uses regex to search for "80" within the 5th column of the `netstat -atnp` command output   netstat -atnp |awk '$5 ~ /80$/ {print $0}' Will do the same, making sure the string search looks for "80" at the end of a string netstat -atnp |awk '$5 ~ /:80$/ {print $0}' Will do the same, making sure the string search looks for "80" at the end of a string
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Red Hat Addresses Critical Firefox Vulnerability

On April 26th, 2016, Red Hat 5, 6, and 7 along with its community-supported counterpart CentOS have released a major new Firefox upgrade to address a number of Critical vulnerabilities in the Extend Support Release (ESR) version of Mozilla's browser software.  The version number jumps to 45 from the current 38.  According to the Security Advisory , Mozilla reported that the Firefox version available for Enterprise Linux distributions--i.e. 38.8--could allow  "A web page containing malicious content could cause Firefox to crash or, potentially, execute arbitrary code with the privileges of the user running Firefox. ( CVE-2016-2805 , CVE-2016-2806 , CVE-2016-2807 , CVE-2016-2808 , CVE-2016-2814 )" Upstream, Mozilla's Security Advosories page for the Extended Support Release ( ESR ) of Firefox tracks this issue and has some relevant links for the different vulnerabilities addressed by this major update. firefox-45.1.0-1.el7_2.src.rpm Buffer Overflow in libs
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RHEL 7 and CentOS 7 syslog Rate Limit

https://access.redhat.com/solutions/1417483 In RHEL 7 there is rate-limiting both in systemd-journald and in rsyslog's imjournal module Lower Ratelimit Interval Lower the interval for rate-limiting and increase the burst level in order to minimize the possibility of losing log messages when the threshold is reached for the specified number of messages logged within the specified interval. Rate-limiting is specific to each process, so there's usually no reason to change this. It is also inadvisable to disable this feature entirely! grep -i rate /etc/systemd/journald.conf #RateLimitInterval=30s #RateLimitBurst=1000 RateLimitInterval=10s RateLimitBurst=3000 grep -i rate /etc/rsyslog.conf #$imjournalRatelimitInterval 600 <--default $imjournalRatelimitInterval 300 $imjournalRatelimitBurst 30000 journal corruption journalctl --verify journalctl --force
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Centos 7 pulseaudio

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Centos 7 doesn't come with an option for `awesome-wm` installation.  Therefore, the only way to make use of this light-weight tiling manager one has to enable Fedora 19 repo or build the package from source.  For the Fedora 19 repo approach, see: https://gist.github.com/ILMostro/1909a50e1858d0ee7e10 To use without GDM, GNOME's display manager, and without gnome services, one has to be aware of certain shortcomings that the gnome-services provide by default.  One such shortcoming is the lack of built-in Sound and Volume management.  Never fret, though, as there is a solution; namely, the PulseAudio-focused tools pavucontrol and pavumeter .  These packages are available from the " nux-desktop " repository available at at http://li.nux.ro/repos.html . nux-desktop My unofficial, as-is, not for profit RPM repositories for EL (RHEL, CentOS, ScientificLinux etc): These repos may or may not be up to date or behave the way you expect them to; use them at yo
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