Preventing DDoS Attacks August 17th, 2010
In this article I am trying to explain what DDOS is and how it can be prevented. DDOS happens due to lack of security awareness of the network/server owners. On a daily basis we hear that a particular machine is under DDOS attack or NOC has unplugged the machine due to DDOS attack . So DDOS has become one of the common issues in this electronics world. DDOS is like a disease which doesn’t have an anti-viral developed. So we should be carefull while dealing with it . Never take it lightly. In this article i am trying to explain the steps/measures which will help us defend from DDOS attack ,up to a certain extend .
What is a DDOS attack?
Simply said, DDOS is an advanced version of DOS attack . Like DOS , DDOS also tries to deny the important services running on a server by broadcasting packets to the destination server in a way that the Destination server cannot handle it. The speciality of the DDOS is that, it relays attacks not from a single network/host like DOS. The DDOS attack will be launched from different dynamic networks which has already been compromised.
Normally, DDOS consists of 3 parts . One is the Master ,Other the slave and atlast the victim. The master is the attack launcher ie the person/machine behind all this,sound’s COOL right . The slave is the network which is being compromised by the Master and Victim is the target site/server . Master informs the compromised machines, so called slaves to launch attack on the victim’s site/machine. Hence its also called co-ordinated attack.
In my term, Master is said to be the Master Brain, Slave is said to be the launch pad for the attack and Victim is the target.
How do they Do it? Read the rest of this entry »
Posted in CentOS, debian, fedora, feebsd, linux, Networking, ubuntu, web development | 1 Comment »
Secure Email Server On Centos June 4th, 2010
Qmailtoaster is a project whose purpose is to install Qmail with RPMs on RPM based Linux and these RPMs are source RPMs. The advantage of Qmailtoaster is that it contains all patches needed for Qmail for example domainkeys etc.
Included Featureset by Qmailtoaster
- Source RPM packages easily rebuilt for multiple distributions
- SMTP with SMTP-AUTH, TLS, REMOTE-AUTH
- DomainKeys, SPF “Sender Policy Framework” and SRS “Sender Rewriting Scheme”
- Integrated SpamAssassin, ClamAV and Simscan
- Warlord virus and worm loader realtime MIME signature scanning
- CHKUSER 2.0 functions for qmail-smtpd
- Qmail-Tap provides email archive capability
- Virtual Domains and Virtual Users using MySQL
- Autoresponder for vacation/away from office messages
- Integrated Mailing List (ezmlm)
- Web-based email system using Squirrelmail
- Web-based administration tools
- POP3, POP3-SSL, IMAP and IMAP-SSL
- Submission port (587) allows roaming users to skip RBL checks and port 25 blocks
- eMPF patch for advanced policy control over email
Qmailtoaster has support for RHEL/CentOS (3.x, 4.x, 5.x , Fedora, Suse, Mandriva. We are going to install Qmailtoaster for CentOS 5.x
Prerequisites: Install Centos 5 base system, remaining packages and dependencies will be installed automatically with qmailtoaster scripts.
1) Configuration Read the rest of this entry »
Posted in CentOS, databases, linux, mysql, Networking | No Comments »
