Matias Barrios's questions

I have tightvnc server running on my Xubuntu 16.04. I can then run this command :

xvnc4viewer 192.168.1.2:5901

I can connect successfully to my machine but the only thing I see is this :

I guess that the reason why is because of a wrong config from my part. This is my config file :

#!/bin/sh

xrdb $HOME/.Xresources
xsetroot -solid grey
x-terminal-emulator -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
x-window-manager &
# Fix to make GNOME work
#export XKL_XMODMAP_DISABLE=1
/etc/X11/Xsession
# fix to make xfce work:
startxfce4 &

Can someone explain to me what am doing wrong on here? I want to see the desktop as I do when sitting on front of my server machine.

So I installed the daemon and configure it as :

matias@~ 
 $ cat /etc/lsyncd/lsyncd.conf.lua 
settings {
        logfile = "/var/log/lsyncd/lsyncd.log",
        statusFile = "/tmp/lsyncd.stat",
        statusInterval = 1,
        verbose = false,
}

sync {
        default.rsync,
        source    = '/home/matias/Remoto',
        target    = '[email protected]:./Remoto',
        delay     = 1,
    rsync= {
        owner = true,
        perms = true,
        group = true,
        acls = true,
        verbose = true,
        rsh = "/usr/bin/ssh -i /home/matias/.ssh/id_rsa.pub -p 22 -o StrictHostKeyChecking=no"
    }
}

I can see the daemon is up and running :

matias@~ 
 $ sudo systemctl status lsyncd
[sudo] password for matias: 
● lsyncd.service - LSB: lsyncd daemon init script
   Loaded: loaded (/etc/init.d/lsyncd; bad; vendor preset: enabled)
   Active: active (exited) since jue 2020-01-23 16:18:05 -03; 3h 28min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 13723 ExecStop=/etc/init.d/lsyncd stop (code=exited, status=0/SUCCESS
  Process: 13731 ExecStart=/etc/init.d/lsyncd start (code=exited, status=0/SUCCE

ene 23 16:18:05 lenovoI5 systemd[1]: Starting LSB: lsyncd daemon init script...
ene 23 16:18:05 lenovoI5 lsyncd[13731]:  * Starting synchronization daemon lsync
ene 23 16:18:05 lenovoI5 lsyncd[13731]:    ...done.
ene 23 16:18:05 lenovoI5 systemd[1]: Started LSB: lsyncd daemon init script.

And if I run journalctl I can see this :

matias@~ 
 $ sudo journalctl -u lsyncd 
-- Logs begin at jue 2020-01-23 10:20:58 -03, end at jue 2020-01-23 19:47:45 -03
......
ene 23 16:06:46 lenovoI5 lsyncd[13218]: Error: error preparing /etc/lsyncd/lsync
ene 23 16:06:46 lenovoI5 lsyncd[13218]:    ...fail!
ene 23 16:18:05 lenovoI5 systemd[1]: Starting LSB: lsyncd daemon init script...
ene 23 16:18:05 lenovoI5 lsyncd[13731]:  * Starting synchronization daemon lsync
ene 23 16:18:05 lenovoI5 lsyncd[13731]:    ...done.
ene 23 16:18:05 lenovoI5 systemd[1]: Started LSB: lsyncd daemon init script

This lines proves that it actually reads the config file and I corrected it :

ene 23 16:06:46 lenovoI5 lsyncd[13218]: Error: error preparing /etc/lsyncd/lsyncd.conf.lua: Parameter "identityFile" unknown. (if this is not a ty
ene 23 16:06:46 lenovoI5 lsyncd[13218]:    ...fail!

I can see the stat log being created :

matias@~ 
 $ cat /tmp/lsyncd.stat 
Lsyncd status report at Thu Jan 23 16:18:05 2020

Sync1 source=/home/matias/Remoto/
There are 1 delays
active Init 
Excluding:
  nothing.


Inotify watching 4 directories
  1: /home/matias/Remoto/
  2: /home/matias/Remoto/Documentos/
  3: /home/matias/Remoto/Archivos/
  4: /home/matias/Remoto/Mas/

The problem is, files and dirs are not getting sync on the remote server. I created folder Mas after restarting the service and after 1 hour it did not get updated.

The weird thing is that it did work when I manual run it as :

lsyncd /etc/lsyncd/lsyncd.conf.lua 

What am I doing wrong?

So I have a function that looks like this. It's an oversimplified example but its enough to demonstrate my issue.

For some reason, I can not get the exit status of the ssh remote command. It does not matter if I give exit 0, or true or if I give a command that throws a success command, the end result is the same, I always get 1.

The thing is, this code works perfectly when ran from a script, but not if I do it from a function.

function hello(){
      while read user password
      do
          ssh -n -q user@host 'exit 0' ; echo $?
      done <<< "$( cat creds.txt )"
}

So I was trying to write a script in an Oracle Linux server and nothing worked. To begin with, there is no double bracket as far as I can tell.

Also, the error messages I get are weird. For instance, this code :

[[ -f 'fake' ]] || { echo "There is a missing file"; } ;

Throws :

Bash : echo not found

I clearly understand the difference between the distribution and the shell you are interacting with, which makes the issue more weird.

I am a long life Centos/Ubuntu scripter so this experience has really been a bummer.

Can someone elaborate any other differences I Should be aware in this new environment?

I have a CentOS 7 server in which I opened up ports for SNMP connections.

Even though I can see the ports open here:

[matias@Centos_7_VM ~]$  sudo firewall-cmd --list-all
[sudo] password for matias:
public (active)
  target: default
  icmp-block-inversion: no
  interfaces: ens33
  sources:
  services: ssh dhcpv6-client
  ports: 80/tcp 10050/tcp 50000/tcp 161/tcp 160/tcp
  protocols:
  masquerade: no
  forward-ports:
  source-ports:
  icmp-blocks:
  rich rules:

When I try to hit this port from the outside I always get that it's closed. Even nmap agrees on this:

Starting Nmap 7.01 ( https://nmap.org ) at 2018-08-01 14:52 -03
Nmap scan report for Centos_7_VM (192.168.43.216)
Host is up (0.52s latency).
Not shown: 996 filtered ports
PORT      STATE  SERVICE
22/tcp    open   ssh
80/tcp    open   http
161/tcp   closed snmp
50000/tcp closed ibm-db2

What else can I do to open these ports? (yes, I reloaded firewalld when I initially opened the ports.)

So I am trying to monitor the logs of a VM running Centos 7. Specifically the one giving problems is /var/log/messages. I have changed both the group ownership of the file ( made the pertaining change in logrotate.conf ) and manually on the already created file. Below you can see the permissions of it :

[matias@Centos_7_VM ~]$ sudo ls -lh /var/log/messages
-rw-rwx---+ 1 root zabbix 889K jul 25 10:53 /var/log/messages
[matias@Centos_7_VM ~]$ getfacl /var/log/messages
getfacl: Removing leading '/' from absolute path names
# file: var/log/messages
# owner: root
# group: zabbix
user::rw-
user:zabbix:rwx
group::---
mask::rwx
other::---

But even with all of those changes, the zabbix agent is getting permission denied to read that log. Is there something else blocking that process from reading the file?

Agent log

993:20180725:062459.211 Starting Zabbix Agent [Centos_7_VM]. Zabbix 3.2.11 (revision 76339).
   993:20180725:062459.256 **** Enabled features ****
   993:20180725:062459.257 IPv6 support:          YES
   993:20180725:062459.257 TLS support:           YES
   993:20180725:062459.257 **************************
   993:20180725:062459.257 using configuration file: /etc/zabbix/zabbix_agentd.conf
   993:20180725:062459.303 agent #0 started [main process]
   999:20180725:062459.359 agent #1 started [collector]
  1003:20180725:062459.396 agent #2 started [listener #1]
  1004:20180725:062459.406 agent #3 started [listener #2]
  1005:20180725:062459.413 agent #4 started [listener #3]
  1007:20180725:062459.472 agent #5 started [active checks #1]
  1007:20180725:105103.700 active check "log[/var/log/messages,(?i)error]" is not supported: Cannot open file "/var/log/messages": [13] Permission denied

I have been trying to get information about the hardware itself from Cisco routers but I was unable to find that on Google. It seems weird I cant find that info neither on Cisco page itself.

My question is, can someone direct me to a page where I can get the CPU, the amount of memory and the overall hardware features of an enterprise Cisco router?

Thanks!

So, I am using Zabbix to monitor my server. At / file system I have 63 GB free. So I wanted to fake a huge file on that directory to see if the Zabbix graphs would correctly show that the used space had increased. So I ran this :

cd / && sudo fallocate -l 50000000000 archivogrande.txt

Which is working correctly and creating a file of approximately 50 GB. Unfortunately, Zabbix graph does not get updated. I can still see that there is 63 Gb free when actually it should say 17. The graph is getting updated every 10 seconds by the way.

So, my question is, regardless of what Zabbix might or might not doing wrong here, is my command actually doing what I expected? Would monitoring software correctly see the increase in used space, even if its not a "real" file?