DevOps Engineer
This article explains the most commonly used Email protocols on the internet – POP3, IMAP, and SMTP
587 vs. 465
These port assignments are specified by the Internet Assigned Numbers Authority (IANA):
Port 587: [SMTP] Message … Read more
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.
/etc/fail2ban/filter.d/custom.conf
[Definition]
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
iptables-save > ~/iptables-`date +%Y%m%d_%H%M%S`.bak
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
iptables-restore < bak.file
A Sender Policy Framework (SPF) record 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
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:
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