Archive for the ‘Linux’ Category
Posted by jpluimers on 2016/07/08
Multihoming without BGP with home routers and Linux. Need to apply this on OpenSuSE one day: HOWTO: Multirouting with Linux : Luke Cyca Dot Calm.
Basically it does Multirouting of Sessions using NAT, routing tables, rules, removal of the default routing and adding a round robin routing, fixing DNS, adding more rules and creating a failover script.
In case it ever goes offline: the WayBack Machine link.
Some more background research links:
–jeroen
Posted in *nix, Linux, openSuSE, Power User, SuSE Linux | Leave a Comment »
Posted by jpluimers on 2016/06/22
Woof is a small simple stupid webserver that can easily be invoked on a single file. Your partner can access the file with tools he trusts (e.g. wget). No need to enter passwords on keyboards where you don’t know about keyboard sniffers, no need to start a huge lot of infrastructure, just do a
$ woof filenameand
tell the recipient the URL woof spits out. When he got that file, woof will quit and everything is done.And when someone wants to send you a file, woof has a switch to offer itself, so he can get woof and offer a file to you. …
Woof needs Python on a unix’ish operating system. Some people have used it successfully on Windows within the cygwin environment.
Source: Woof – simply exchange files
Works from homebrew on OS X.
via: Web Offer One File – Thomas Mueller (dummzeuch) – Google+
Source: Web Offer One File
–jeroen
Posted in *nix, *nix-tools, Apple, BSD, Home brew / homebrew, Linux, Mac, Mac OS X / OS X / MacOS, Power User | Leave a Comment »
Posted by jpluimers on 2016/06/16
Since quite a few commands that you regularly see mentioned on the web have been removed from OpenSuSE net-tools, I’ve created a few bash aliases in /etc/bash.bashrc.local below.
Note the original commands are not good have been deprecated for years on various distros and therefore removed:
# stuff removed from net-tools
# see https://features.opensuse.org/317197 and https://build.opensuse.org/package/view_file/network:utilities/net-tools/net-tools.changes
## Because of changes on Thu Apr 10 12:33:41 UTC 2014
alias "arp=echo 'use \"ip neigh\" or \"ip -r neight\"' && ip neigh"
alias "ifconfig=echo 'use \"ip a\"' && ip a"
alias "netstat= echo 'use \"ss\" or \"ss -r\"' && ss"
alias "route=echo 'use \"ip r\"' && ip r"
## Because of changes on Sun Mar 29 00:41:21 UTC 2015
alias "ipmaddr=echo 'use \"ip maddr\"' && ip maddr"
alias "iptunnel=echo 'use \"ip tunnel\"' && ip tunnel"
Some bits of the net-tools change-log:
-------------------------------------------------------------------
Sun Mar 29 00:41:21 UTC 2015 - jengelh@inai.de
- ipmaddr and iptunnel are obsolete too, move them to subpackage.
(Superseded by `ip maddr` and `ip tunnel`)
- remove redundant %clean section
-------------------------------------------------------------------
Thu Apr 10 12:33:41 UTC 2014 - mmarek@suse.cz
- Move arp, ifconfig, netstat and route to a -deprecated subpackage
(fate#317196, fate#317197)
- Drop the rarp tool, which has been broken since kernel 2.3
Note that the -lntu parameter seems to be the same for both ss and netstat: [WayBack] Get a list of Open Ports in Linux – Super User
–jeroen
via File net-tools.changes of Package net-tools – openSUSE Build Service.
Posted in *nix, *nix-tools, bash, bash, Development, Linux, openSuSE, Power User, Scripting, Software Development, SuSE Linux | Leave a Comment »
Posted by jpluimers on 2016/06/13
After zypper dup (dist-upgrade) or zypper up (update) a zypper ps will list processes using deleted files (i.e. processes that likely need to be restarted).
Some processes that can be restarted without reboot:
To research
- dhcpcd
- rs:main
- agetty
- lvmetad
- agetty
- dmeventd
Some processes that require a reboot:
–jeroen
Posted in *nix, ESXi5, ESXi5.1, ESXi5.5, ESXi6, Linux, openSuSE, Power User, SuSE Linux, Virtualization, VMware, VMware ESXi | Leave a Comment »
Posted by jpluimers on 2016/06/09
I long while after asking TUMBLEWEED: local console yast linedrawing characters garbage after first reboot, I researched the issue further.
First the workaround:
It is enough if any user on any console (for which /usr/bin/tty will usually show /dev/tty#) runs /bin/unicode_start.
After that, any user that logs on on any console will get the correct line-drawing characters with yast.
Then about the problem:
It looks like the problem is that during boot, nothing calls /bin/unicode_start. This was a solved bug, but seems to be back in Tumbleweed so I posted a comment to the bug.
I don’t think it is related to a truckload of PuTTY UTF-8 line-drawing issues like below. I’ve included them just for reference in any case proves me wrong (:
Same for changing unicode_start by hand:
–jeroen
via:
Original question thread:
Read the rest of this entry »
Posted in *nix, Linux, openSuSE, Power User, SuSE Linux | 1 Comment »
Posted by jpluimers on 2016/06/01
I needed to find the symlinks in /etc pointing to directories and know both the name and place they point to.
revue:~ # ls -al `find -L /etc/ -xtype l -type d`
find: ‘/etc/ssh/broken/ssh_host_dsa_key’: Too many levels of symbolic links
find: ‘/etc/ssh/broken/ssh_host_ecdsa_key’: Too many levels of symbolic links
find: ‘/etc/ssh/broken/ssh_host_key’: Too many levels of symbolic links
find: ‘/etc/ssh/ssh_host_ecdsa_key’: Too many levels of symbolic links
find: ‘/etc/ssh/ssh_host_dsa_key’: Too many levels of symbolic links
find: ‘/etc/ssh/ssh_host_key’: Too many levels of symbolic links
lrwxrwxrwx 1 root root 19 May 7 15:43 /etc/apparmor.d/cache -> /var/cache/apparmor
lrwxrwxrwx 1 root root 6 Sep 28 2014 /etc/rc.d -> init.d
lrwxrwxrwx 1 root root 26 May 23 13:50 /etc/squid/errors -> /usr/share/squid/errors/de
lrwxrwxrwx 1 root root 28 Mar 25 22:07 /etc/ssl/certs -> /var/lib/ca-certificates/pem
lrwxrwxrwx 1 root root 18 Apr 30 14:20 /etc/xdg/systemd/user -> ../../systemd/user
–jeroen
via: bash – How do I find all of the symlinks in a directory tree? – Stack Overflow.
Posted in *nix, *nix-tools, bash, bash, Development, Linux, openSuSE, Power User, Scripting, Software Development, SuSE Linux | Leave a Comment »
Posted by jpluimers on 2016/05/27
openSuSE provides a rolling release called tumbleweed. Given the very different nature, traditional means of updating don’t work (I added some links to the text):
You should use “zypper dup” to keep your system up-to-date, YaST->Online Update is useless on Tumbleweed.
You can use the update applet, YaST->Software Management, or “zypper up” as well most of the time, but those won’t be able to cope with _all_ changes in Tumbleweed, e.g. they might have problems when packages are dropped or renamed.
There are mixed opinions on using rolling releases, for instance Are rolling release Linux distros better than fixed releases? | ITworld.
But I have the feeling that many of them are ready for real primetime, and Windows 10 seems to follow the rolling-release direction too. It’s a matter of the process leading to the rolling updates being very well, and offering customers a choice when to install updates.
Edit 20160527:
Richard Brown (@sysrich), Geek, Linux engineer. openSUSE Chairman, chimed in on Twitter:
I prefer `zypper dup –no-allow-vendor-change`. It is safer when additional repos are present. I alias it as `zypper-twup`
–jeroen
via TUMBLEWEED: Tumbleweed Repos.
Posted in *nix, Linux, openSuSE, Power User, SuSE Linux | 1 Comment »
Posted by jpluimers on 2016/05/26
Thanks Adrian W for providing the below example in your answer about obtaining GLUE record information for a domain.
It is an excellent showcase for the $IFS Internal Field Separator available in any nx shell.
In this case it is used to get the TLD (top-level domain) from the domain name specified at the command-line.
After that, it obtains the name servers for that TLD, and queries the glue records there, both using dig.
Here is a little shell script which implements Alnitak’s answer:
#!/bin/sh
S=${IFS}
IFS=.
for P in $1; do
TLD=${P}
done
IFS=${S}
echo "TLD: ${TLD}"
DNSLIST=$(dig +short ${TLD}. NS)
for DNS in ${DNSLIST}; do
echo "Checking ${DNS}"
dig +norec +nocomments +noquestion +nostats +nocmd @${DNS} $1 NS
done
Pass the name of the domain as parameter:
./checkgluerecords.sh example.org
–jeroen
via domain name system – How to test DNS glue record? – Server Fault.
Posted in *nix, Apple, bash, Development, DNS, Linux, Mac, Mac OS X / OS X / MacOS, Mac OS X 10.4 Tiger, Mac OS X 10.5 Leopard, Mac OS X 10.6 Snow Leopard, Mac OS X 10.7 Lion, openSuSE, OS X 10.10 Yosemite, OS X 10.8 Mountain Lion, OS X 10.9 Mavericks, Power User, Scripting, Software Development, SuSE Linux | Leave a Comment »
Posted by jpluimers on 2016/05/03
After a recent big update to OpenSuSE Tumbleweed, I could not ssh into my system any more.
Symptoms
The ssh client side would report a Read from socket failed: Connection reset by peer which I misinterpreted as the sshd not running at all.
Luckily the server is a VM, so I could reach the console. There I saw this:
sshd trying to load files it shouldn’t
The files should not be loaded as they are not specified in the sshd_config file:
dsa and ecdsa not specified in the config file
So I knew something was broken. After reading some messages in the forums.opensuse.org I got at Bug 977812 – sshd killed by SIGSYS on client connection
The cause
As usual with such issues the cause seems a combination of factors:
And we have the culprit, I believe: together with the glibc upgrade, openssl
was updated from 1.0.2g-1.1 to 1.0.2-2.12 which brought, among others, patch
openssl-urandom-reseeding.patch.
Temporary fix
A temporary fix is to comment out a line in /etc/sshd_config so you get this diff:
-UsePrivilegeSeparation sandbox # Default for new installations.
+# UsePrivilegeSeparation sandbox # Default for new installations.
Be sure to undo this as soon as you’ve received a final fix.
Final fix
A final fix is being fast-tracked so it appears in Tumbleweed soon.
I will report after deployment of [opensuse-factory] New Tumbleweed snapshot 20160502 released! as I think it contains the fix.
Aftermath
I already knew about openQA: Test summary which lists the builds, but not the changes in the builds.
Reading through Information Board or the like for Tumbleweed I found the openSUSE Mailinglist Archive: opensuse-factory which does the announcements and release notes for Tumbleweed.
It had both the announcement of the “big patch”, ssh bug report and temporary fix:
–jeroen
Posted in *nix, Communications Development, Development, Internet protocol suite, Linux, openSuSE, Power User, SSH, SuSE Linux, TCP, Tumbleweed | 2 Comments »
The Wiert Corner - irregular stream of stuff 