firewall – Internetblog.org.uk

Server Security Tips

Mon, 26 Jul 2010 15:51:31 +0000

1. Do not allow direct root/administrator login
2. Make sure passwords are secure and changed regularly (by force if necessary)
3. Use a network firewall, such as APF
4. Use an application firewall, such as ModSecurity
5. Chroot all non-root users to keep them out of system directories
6. Use virus scanners and spam filters
7. Close mail server open relays
8. Keep all software and scripts up-to-date
9. Test your server for security holes
10. Keep up on the latest security news
11. Use SSL for secure data transactions
12. Set permissions as strictly as possible on any web-accessible files

Image Source: Wikimedia Commons

Server Networking Tips

Mon, 26 Jul 2010 16:47:58 +0000

Over the past year, we have covered many networking tips for servers. Here is a brief summary of the most important networking tips you should keep in mind for your dedicated server.

1. Use both a router firewall and a software firewall
2. Your name servers should be hosted on at least two different servers
3. If you use content delivery services, make sure they have servers close to your primary users
4. Block all ports except the most essential (i.e. web server, ssh, ftp)
5. Use traceroute and dns lookups to test network connectivity issues
6. Be sure to follow Internet standards with your DNS records
7. Use SSH, SCP, SFTP, and other secure protocols whenever you need to connect to your server

Photo Source: Flickr

Is a router firewall enough to protect my server?

Thu, 22 Apr 2010 17:03:20 +0000

Many web hosting providers and dedicated server data centers will provide router-level firewalls for their customers, mainly as a precaution to protect their infrastructure. A bot, virus, or other form of malware that gets into a single network can spread from server-to-server very quickly.

On some home networks, a router firewall may be the only one used. The problem with relying on your service provider to block unwanted incoming traffic is that you have no control over what is blocked or if anything gets blocked at all. Furthermore, larger web hosts may have thousands or even hundreds of thousands of servers all connected through a complex network of routers. Any device on the same router as you could become a potential attacker or host to a bot.

Because of that reality, relegating responsibility for your server’s security to your web host is not only a matter of putting trust in the provider, but also involves trusting everyone else in your network. That is not a risk you should be willing to take. Install a software firewall, such as APF, on your server, and consider additionally installing an application firewall, such as ModSecurity.

Photo Source: Flickr

How to open and close ports with iptables

Tue, 24 Nov 2009 16:10:22 +0000

Question: How do I open and close ports with an iptables firewall setup?

Answer: You can easily open ports on a dedicated server with these simply commands. Depending on whether you need to open a UDP or TCP port, use one or both of the following:

iptables -A INUPT -p tcp –dport -j ACCEPT iptables -A INUPT -p udp –dport -j ACCEPT
And to close a port, enter:
iptables -A INUPT -p tcp –dport -j DROP iptables -A INUPT -p udp –dport -j DROP

Then, save and restart iptables:

service iptables save service iptables restart

You can keep track of which ports have been opened and closed by viewing the /var/log/messages file.

Photo: Flickr

Advanced Policy Firewall (APF)

Thu, 12 Nov 2009 21:24:51 +0000

Few issues with dedicated servers are more important than security, and no security software is overlooked more than firewalls. Most people expect firewalls to work the way they want them to without any effort. While that is impossible, there is a free software firewall solution available that makes installation, setup, and maintenance easy. Its name is Advanced Policy Firewall (APF) by R-fx Networks.

It relies on iptables and provides the user with an easy command line interface for configuration. APF allows for full customization of features, particularly useful for system administrators who need options. APF is known to work on numerous Linux distributions, including Redhat Enterprise Linux, CentOS, Debian, and Slackware.

APF is free software, licensed under the GNU General Public License. R-fx Networks also offers several other security software packages for servers, including brute force detection and system integrity monitoring.

Photo Source: stock.xchng

China to Install "Green Dam" Content Filter on New Computers

Mon, 08 Jun 2009 18:40:03 +0000

The Chinese government has issued an order requiring all computers sold in China to have a government-sanctioned content filter installed.

Known as “Green Dam,” the software filters obscene images and words. Computer makes must preinstall it on all computers sold in the country starting July 1.

China is notorious for its strict Internet censorship, but security experts are afraid Green Dam could be used to monitor personal computer use, collect personal information, and block a greater range of content.

American computer makers in the region have already expressed dissent. “Many of us are going to take it in the neck with this mandate,” said one tech executive. “It has put people into five-alarm mode.”

The software has already been downloaded 3.2 million times. Its installation has been required on all school computers since May. Users have reported that the content filter is buggy, at times ineffective, and some have reported system crashes associated with the software, which is only available on Windows for now.

Source: New York Times