... Department[*]
UNAM (Universidad Nacional Autónoma de México) is the largest and most important University in Mexico. Within DGSCA (Dirección General de Servicios de Cómputo Académico), its largest computer related division, lies the Computer Security Department, the most serious and important emergency response team and computer security research area in Mexico. Its URL is http://www.asc.unam.mx
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... inspection[*]
Analyzing each incoming packet, working not only on source and destination of the packages, but keeping track on whether the connection was originated by which party (often allowing outbound connections while rejecting inbound connections) and the packet sequence (avoiding, to a certain degree, connection hijacking).
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... MacOS.[*]
MacOS X is a full-fledged BSD-derived Unix system, and users are encouraged to take advantage of that fact. Although MacPerl is available for older MacOS versions, it is not reccomended anymore because of the lacking functionality the old MacOS enviroment imposed on its development; regular Perl should be used instead.
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... character.[*]
For most TCP/IP protocols, the new line character is a carriage return followed by a line feed, also written as CR-LF or \r\n
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... free[*]
Free as in freedom, not only price. The author reccomends always using free software, for it is almost always more thoroughly tested, secure and efficient than any propietary counterpart. Choosing free software also allows any people interested in contributing to the project to do so with the least hassle possible.
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... projects.[*]
Quoting Larry Wall, the inventor of Perl: Perl makes easy things easy, and difficult things possible.
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... innecesarily[*]
There are several ways of compiling Perl code. However, as of Perl version 5.005, they are still regarded as experimental. With the recent announcement of Perl version 5.6 this may change, but until the new version is thoroughly tested and has a wide user base, the author decided to stick with 5.005's limitations.
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... requests[*]
A computer suffering a Denial of Service (DoS) attack means it is being purposefully presented with many more requests than it can handle at a time, thus overloading it and forcing it to deny service to legitimate users. Using technology available today, a DoS attack is very difficult to detect, and even harder to stop.
In March 2000 the first reports of Distributed Denial of Service (DDoS) surfaced. They refer to a variety of DoS attack which is not carried out by a single computer, but by many simultaneous, being much stronger than any previously reported DoS.
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... systems.[*]
Legally, Linux, FreeBSD, NetBSD and OpenBSD are not Unix systems, even though they behave as if they were. This is because Unix is a registered trademark of Bell Labs, and royalties have not been paid to use the Unix name. They do, however, adhere to the POSIX standard which defines Unix systems. Thus, they are referred to as Unix-like, but anything regarding Unix applies also to these operating systems.
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... ssh[*]
ssh --secure shell-- is a relatively recently introduced protocol designed to replace and enhance telnet and the r-commands (rlogin, rcp, rsh). They require replacement because they are protocols which transmit information in clear text, applying no encryption and thus allowing anyone connected to the same network as the host or the client to intercept all of the information, or even --with relatively trivial cracking utilities-- to hijack the connection. ssh also enhances telnet and rlogin by providing encrypted tunnels by which other protocols --usually, X-Window sessions-- can be routed, while encrypting also their information. It includes also scp, designed to allow encrypted file transfers between computers.
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... IETF.[*]
RFC stands for Request For Comments, IETF stands for Internet Engineering Task Force
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... client[*]
Client is defined as the computer requesting a service, regardless of its formal role
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... server[*]
A server, likewise, is the computer attending the request from a client
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... politeness.[*]
Although nowadays SMTP is practically only used over a TCP/IP protocol stack, RFC 821 contemplates other possible network protocols, such as the Arpanet's NCP (Network Control Protocol), X.25 and NITS (Network Independent Transport Service).
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... lockable[*]
Every serious multiuser operating system will allow for a method of telling if a file is currently in use and denying write access to it, in order to preserve the file's integrity.
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... host[*]
defined with the .rhosts file in the user's home directory or with the hosts.equiv file in the server's /etc directory. This is not reccomended in open or large networks, as a simple IP spoofing may very easlily compromise the systems' security
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...undef[*]
The value undef is a special value used by Perl to indicate that a variable has no value. It is analogue to C's NULL. Note that undef is not equal to zero -- undef is undef.
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... forks[*]
In Unix, a process can continue part of its execution in the background detaching itself from the main part by calling the fork() system call. A new process ID (PID) is given to the newly created process (referred to as the child process). The base process (referred to as the parent process) gets the child PID number and continues execution.
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... itself[*]
Garbage collection is the process of freeing up unused chunks of memory, closing files and sockets when they are no longer referenced and taking care of destroying unneeded objects. One of Perl's greatest strengths is that it will handle all the garbage collection for us. However, it is considered a good programming practice to always close what has been opened and destroy every unused object. This can also be useful when restarting or reconfiguring the wrapper: Instead of restarting the program or sending the necessary instructions to modify the current wrapper object's behavior, sometimes it is much easier to destroy the object and create it again.
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... system[*]
For a complete list of signals, refer to the signal(7) man page on most Unix and Unix-like systems. 19 signals are defined in the POSIX .1 definition, and many more are supported by most systems.
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...caught[*]
Catching a signal means that when the signal arrives to the process, the process can decide to call a function to handle the event instead of following the default action, which usually is to terminate the process
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... cluster[*]
A cluster is any number of computers which appear to be only one, either by using special hardware architecture or software dedicated to join them.
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... Mosix[*]
for more details, visit http://www.beowulf.org/ for Beowulf, http://www.mosix.cs.huji.ac.il/ for Mosix
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... 192.168.0.254[*]
The IP addresses were not randomly chosen; networks 10.x.x.x, 172.16.x.x to 172.31.x.x and 192.168.x.x are reserved for private, internal use. For more information on this, please check RFC 1918, Address Allocation for Private Internets, Y. Rekhter et. al.
There is also an implicit standard between many network administrators, making their routers and firewalls use the highest available IP addresses of each subnetwork.
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... port.[*]
Please note that, while the ipchains line in rc.local forbids any incoming connection to reach port 10025 on IP address 192.168.0.1, the wrapper's destination IP address is 127.0.0.1, which not only is easily accesible from within the server, not being affected by this rule, but also is inaccessible from any outside machine.
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