LVM Extend ROOT with EXT4 File System

Problem: root partition was full.

$ df -h
Filesystem                         Size  Used Avail Use% Mounted on
udev                               3.9G     0  3.9G   0% /dev
tmpfs                              799M   67M  732M   9% /run
/dev/mapper/silver--vg-root         37G   36G     0 100% /
...
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Postfix Monitor Sent Mails and Block Domains

Check how many mails has been sent via postfix.

If the number is to big, it must be hacked by someone on some services.

sudo grep "status=sent" /var/log/mail.log | egrep -ve 'postfix/(cleanup|pickup|master|qmgr|smtpd|local|pipe)' | wc -l
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IP Reserved Loopback and Private Addresses

Range Start Address

Range End Address

“Classful” Address Equivalent

Classless Address Equivalent

Description

0.0.0.0

0.255.255.255

Class A network 0.x.x.x

0/8

Reserved.

10.0.0.0

10.255.255.255

Class A network 10.x.x.x

10/8

Class A private address block.

127.0.0.0

127.255.255.255

Class A network 127.x.x.x

127/8

Loopback address block.

128.0.0.0

128.0.255.255

Class B network 128.0.x.x

128.0/16

Reserved.

169.254.0.0

169.254.255.255

Class B network 169.254.x.x

169.254/16

Class B private address block reserved for automatic private address allocation. See the section on DHCP for details.

172.16.0.0

172.31.255.255

16 contiguous Class B networks from 172.16.x.x through 172.31.x.x

172.16/12

Class B private address blocks.

191.255.0.0

191.255.255.255

Class B network 191.255.x.x

191.255/16

Reserved.

192.0.0.0

192.0.0.255

Class C network 192.0.0.x

192.0.0/24

Reserved.

192.168.0.0

192.168.255.255

256 contiguous Class C networks from 192.168.0.x through 192.168.255.x

192.168/16

Class C private address blocks.

223.255.255.0

223.255.255.255

Class C network 223.255.255.x

223.255.255/24

Reserved.

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