What do we have to prepare before upload in Amazon

Create these your application icon for various dimension in png format:

1. Small icon 114 x 114px PNG (with transparency)
2. Large icon 512 x 512px PNG (with transparency)

Promotional image (Recommended) 1024 x 500px (landscape only) PNG or JPG
Create 3 Screen shoot 800X480 or 480x800.

What do we have to prepare before upload our application in Google Play Store

Create your application icon in 512x512 px. in Android Studio, use Image Asset to generate application icon (include for Google Play Store) 

Google play publishing a new application, from dashboarrd
1. Set privacy policy (url, privacy policy must image)
2. App access
3. Ads
4. Content rating
5. Target audience
6. News apps
7. Data safety
8. Government apps
9. Financial features
10. Health
11. Select an app category and provide contact details
12. Set up your store listing (Store presence -> Main store lisiting)
13. Select countries and regions
14. Create closed & Open testing release (the same version)
15. Create a new release
16. Preview and confirm the release
17. Send the release to Google for review

Store presence -> Main store lisiting
1. App name
2. Short description
3. Full description
4. App icon
5. Feature graphic demension 1024 w x 500 h in JPG or 24-bit PNG (no alpha
6. Phone screenshots (8 images)

https://developer.android.com/distribute/console

Blocking IP by country for some ports using ipset

To block IP by country, we need IP blocks for particular country. This step needs IP blocks from http://ipdeny.com/.
We need to convert IP blocks into ipset format, this bash script will do:

1. Download block ip by country from http://www.ipdeny.com
2. Convert block ip into ipset format

For IPV4: http://www.ipdeny.com/ipblocks/data/countries/ For IPV6: http://www.ipdeny.com/ipv6/ipaddresses/blocks/
Here is bash script blockcountryip.sh or download from https://garasiku.web.id/ipset/blockcountryip.sh.txt:
#!/bin/bash
# 2017-05-23

if [ "$1" != "" ]; then
 echo $1
 # download ipv4 block
 echo "Download ipv4 $1"
 wget http://www.ipdeny.com/ipblocks/data/countries/$1.zone -O zone.ipv4.$1
 # download ipv6 block
 echo "Download ipv6 $1"
 wget http://www.ipdeny.com/ipv6/ipaddresses/blocks/$1.zone -O zone.ipv6.$1
 mfile1="./zone.ipv4.$1"
 ofile1="./ipv4.ipset.$1"
 touch $ofile1
 echo "creating ipset rules $ofile1 for ipv4"
 echo "create ipv4_$1 hash:net" > $ofile1
 while read line; do
  echo "add ipv4_$1 $line" >> $ofile1
 done <"$mfile1"
 echo "Done creating $ofile1"
 mfile2="./zone.ipv6.$1"
 ofile2="./ipv6.ipset.$1"
 echo "creating ipset rules $ofile2 for ipv6"
 echo "create ipv6_$1 hash:net" > $ofile2
 while read line; do
  echo "add ipv6_$1 $line" >> $ofile2
 done <"$mfile2"
 echo "Done creating $ofile2"
else
 echo "Usage .//blockcountryip.sh countrycode2"
fi
To use this bash script:
# ./blockcountryip.sh [countrycode]
for example to generate IP blocks for China CN
# ./blockcountryip.sh cn
Note: you can download IP block for China from this http://garasiku.web.id/ipset/ipv4.ipset.cn with some additional IP block.
To load it in memory
# ipset restore -! < ipv4.ipset.[countrycode]
[countrycode] is 2 character country code https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2
To apply in iptables
# iptables -A INPUT -p tcp -m multiport --dports [any port you wish] -m set --match-set ipv4_[countrycode] src -j DROP
For example to block all IPV4 from China for port 21, 22, 80, 443 and 2222
# iptables -A INPUT -p tcp -m multiport --dports 21,22,80,443,2222 -m set --match-set ipv4_cn src -j DROP 
# iptables -A INPUT -p udp -m multiport --dports 22,2222 -m set --match-set ipv4_cn src -j DROP
Who will care if I block all of their connection:
# iptables -A INPUT -m set --match-set ipv4_cn src -j DROP
To make it persistent, follow your distribution guide how to load ipset and iptables rules every time system start/restart or network start/restart.
Not Working IPV6
Note:

1. Tunneling SSH may used UDP protocol
2. Proftpd listen on port 2222
3. Port 25 uses to communicate with/to other mail server

My github.com: https://github.com/dedetok/bash-block-ip-by-country
 References:

• http://ipdeny.com/ 
• https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2

Windows: Install/deploy XAMP 7.1.1

We would like to test our application on PHP 7.1. To do that, we need to install/deploy XAMPP 7.1.1.

You can download installer or portable XAMPP 7.1.1 packages at https://www.apachefriends.org/download.html or https://sourceforge.net/projects/xampp/files/ (non installer). I prefered to use portable XAMPP 7.1.1 package, xampp-portable-win32-7.1.1-0-VC14.7z.

XAMPP 7.1.1 required Microsoft Visual C++2015 Runtime. You can download it from Microsoft Visual C++ 2015 Redistributable Update 3 (latest when this article written). Choose your Windows platform that you used, 32 bit or 64 bit. Download and install it.

Extract xampp-portable-win32-7.1.1-0-VC14.7z, into your drive for example C:. It will create folder C:\xampp.

Before you use it, do this to avoid some problems:

1. Edit file C:\xampp\mysql\bin\my.ini
   change key_buffer to key_buffer_size for example:
   ...
   key_buffer to key_buffer_size = 16M
   ...
2. Create folder C:\xampp\mysql\lib\plugin

You may start or stop your apache 

1. Using XAMPP Control "xampp-control.exe"
2. Running on cmd "apache_start.bat" to start and "apache_stop.bat" to stop (I prefere this).

You may start or stop your mysql (MariaDB)

1. Using XAMPP Control "xampp-control.exe"
2. Running on cmd "mysql_start.bat" to start and "mysql_stop.bat" to stop (I prefere this).

Note:

1. XAMPP folder required directly under drive for example C:\xampp, D:\xampp, etc, it may fail to start.
2. Do not rename xampp folder, it may fail to start.

.

Centos 6: csf blocking whois

symptom:

# whois google.com

[Querying whois.verisign-grs.com]

[Unable to connect to remote host]

To solve this problem, edit /etc/csf/csf.conf, make sure outgoing to port 43 and 53 are allowed.

# vi /etc/csf/csf.conf

...

# Allow outgoing TCP ports

TCP_OUT = "20,21,22,25,43,53,80,110,113,443,587,993,995"

...

# Allow outgoing UDP ports

# To allow outgoing traceroute add 33434:33523 to this list

UDP_OUT = "20,21,43,53,113,123"

...

Restart your csf

# csf -r

Done!