How to add bulk IP addresses to DigitalOcean firewall ?

digitalocean

Trying to add bulk IP’s in DigitalOcean firewall? You are in the right place.

DigitalOcean cloud control panel UI doesn’t allow you to paste in multiple IP Addresses at once. That’s a good idea for a UI improvement.

In the meantime you can definitely do it via the API…… Read more

Still Confused With Mail Ports?

This article explains the most commonly used Email protocols on the internet – POP3, IMAP, and SMTP

  • SMTP 25, 2525
  • SMTP-SSL/TLS 587,465
  • IMAP 143
  • IMAP-SSL/TLS 993
  • POP3 110
  • POP3-SSL/TLS 995

587 vs. 465
These port assignments are specified by the Internet Assigned Numbers Authority (IANA):

Port 587: [SMTP] Message … Read more

fail2ban filters – custom rules using regexp

fail2ban

fail2Ban is a very handy tool to prevent a lot of unwanted traffic from consuming bandwidth on your servers. It’s a minimal and relatively simple IDS Type Tool that comes with some predefined filters to automatically lockout potentially dangerous or bandwidth-consuming type attacks.

1. creating a custom filter

/etc/fail2ban/filter.d/custom.conf
[Definition]
 
Read more

Cron job for Automatic Feed updates in Openvas

To get updated content from the feeds you need to run the following scripts (in this order) on a daily base

# crontab -e

0 1 * * * /usr/sbin/greenbone-nvt-sync > /dev/null
0 2 * * * /usr/sbin/greenbone-scapdata-sync > /dev/null
0 3 * * * /usr/sbin/greenbone-certdata-sync > /dev/null

If there … Read more

How to RESET/FLUSH/DELETE all iptables in Linux

Take backup

iptables-save > ~/iptables-`date +%Y%m%d_%H%M%S`.bak

Flush now

iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT

Again to restore from backup

iptables-restore < bak.file
Read more

How to set up an SPF record for your domain?

What are the SPF records?

A Sender Policy Framework (SPFrecord is a type of Domain Name Service (DNS) TXT record that identifies which mail servers are permitted to send an email on behalf of your domain. The purpose of an SPF record is to detect and prevent … Read more

Testing IPSEC VPN Systems with ike-scan

ike-scan is a command-line tool for discovering, fingerprinting and testing IPsec VPN systems. It constructs and sends IKE Phase-1 packets to the specified hosts, and displays any responses that are received.

ike-scan does two things:

  1. Discovery: Determine which hosts are running IKE. This is done by displaying those hosts which
Read more

iptables explained

iptables

Iptables is used to set up, maintain, and inspect the tables of IP packet filter rules in the Linux kernel. Several different tables may be defined. Each table contains a number of built-in chains and may also contain user-defined chains.

Each chain is a list of rules which can match … Read more