Tags » Iptables

Google Compute Engine (GCE) firewall and iptables at VM host

After I click “Allow HTTP” and “Allow HTTPS” in the settings of Centos 7 vm, I can get http or https pages of my site. What? 335 more words


SNMP unresponsive on Storage Cell after Exadata Patching

After a round of Exadata patching, the Storage Cells become unresponsive to SNMP for monitoring tools like OpsViews:

check_snmp_sysinfo CRITICAL - Agent not responding, tried SNMP v1 and v2c… 382 more words


Many users use IPTables in Linux as a firewall, and from a strict point of view, IPTables (IPTables 101) is just a command-line tool that helps administrators define rules and communicate with Linux Kernel. 185 more words

Geek Stuff

Block IP using iptables

In order to block an IP in our Linux server, we need to use iptables:

iptables -A INPUT -s IP-TO-BLOCK -j DROP
service iptables save
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herbie security by obscurity

iptables -t nat -A OUTPUT -p tcp -d {host} –dport {port-mapped} -j DNAT –to-destination {IP:port}


Using Odroid as IP Router

I purchased an Odroid-XU4 for ca. 80 EUR including power-supply and case from Pollin. The original manufacturer is hardkernel. I intended to use this small… 3,146 more words


How to modify SSH remote login port in Linux

SSH: short for Secure Shell, SSH (developed by SSH Communications Security Ltd.) is a secure protocol for remote logins. Using an SSH client, a user can connect to a server to transfer information in a more secure manner than other methods, such as telnet. 120 more words