https://homeostasis.scs.carleton.ca/wiki/api.php?action=feedcontributions&feedformat=atom&user=Krithika 2026-05-02T06:06:37Z User contributions MediaWiki 1.42.1 https://homeostasis.scs.carleton.ca/wiki/index.php?title=SystemsSec_2018W_Lecture_5&diff=21438 2018-01-23T02:35:31Z

<p>Krithika: /* Notes */</p> <hr /> <div>==Notes==<br /> <br /> - Basic structure of the internet<br /> * client =&gt; net =&gt; server<br /> * basic client server model<br /> * processes on client and server talk to each other<br /> * network firewall sits between net and server, protects the network from malicious incoming traffic<br /> * host firewall sits between net and server, sits in front of server<br /> * each process has a unique port number<br /> * IP address identifies hosts<br /> <br /> - IP addresses are very easy to spoof<br /> - Initially, servers would talk to any client, very risky<br /> - Finger daemon lists for finger requests<br /> * process that can find out anyone's personal info (eg. name, phone number, etc.)<br /> * eg: finger soma@homeostasis.scs.carleton.ca<br /> * outputs a &quot;plan&quot; file with user's personal info<br /> <br /> - chargen = character generator<br /> - localhost:631 = url for CUPS<br /> * web-based printer management console for unix systems<br /> * config file has basic access control (ie. IP address restriction)<br /> * not openly available, secure for single host, not so good for multiple hosts (ie. network)<br /> <br /> - security issues?<br /> * different config files for different OS, tedious to setup<br /> * ideally, we want a uniform way of combining policy<br /> <br /> - TCP wrappers &quot;libwrap&quot;<br /> * came before host based, widespread firewall support<br /> <br /> - what is a firewall?<br /> * 2 types: host and network, differs by who enforces the rules<br /> <br /> - what is a vpn?<br /> * virtual private network<br /> * can be problematic, misused if used to download media onto your machine while connected to a company network<br /> * viruses can enter the network this way<br /> <br /> - to increase network security, turn off unnecessary services that don't need to talk over the network like the finger daemon<br /> - outgoing traffic is safe but incoming traffic may not be<br /> - ntpd = network time protocol daemon<br /> - modern architecture uses VMs and containers like Docker<br /> * Processes in Docker separated into groups<br /> * 1 firewall per group</div>

Krithika