Common Application Port Configurations

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Time
21 hours 25 minutes
Difficulty
Intermediate
CEU/CPE
21
Video Transcription
00:00
>> Hey, Cybrarians. Welcome back to
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the Linux plus course here at Cybrary.
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I'm your instructor Rob Goelz.
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In today's lesson, we're going to cover
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common application port configurations.
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So upon completion of this lesson,
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you are going to be able to locate the file
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documenting application service names and ports,
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and we're also going to talk about privileged ports.
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For the Linux plus exam,
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we do need to memorize a few services and ports.
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I think we've been pretty clear about that so far.
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>> We've seen a lot of those hands with fingers,
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>> with string tied around them
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as we've gone through the course.
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Those are the ports we need to remember.
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But in real life, applications, firewalls,
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and system administrators can just look
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at the file /etc/services.
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That /etc/services file holds
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standard application services and
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the ports that are assigned to them by IANA.
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It's also used by utilities such as netstat and UFW.
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Netstat and UFW don't know these ports.
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They just deal with /etc/services and say, "Oh, yeah,
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that's the port we need for FTP or SSH."
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Now, when we're talking about
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port numbers 1 through 1023,
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those are considered privileged ports,
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and applications and
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services on these ports can only
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be run with privileged accounts.
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Right now, privileged accounts are
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accounts that are added to the sudo group on Ubuntu,
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>> or the wheel group on CentOS,
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>> or just the root user.
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>> Hence, these are privileged accounts.
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These ports are designated for
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commonly-used protocols such as mail,
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SMTP port 25,
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and then web traffic, HTTP or HTTPS,
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which are on port 80 or port 443 respectively.
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However, remember what we talked
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about back in Module 17,
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well-known ports are well known by everyone.
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Ports can be modified out of
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caution or as an extra layer of
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protection or obfuscation by going into
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the configuration file for some of these applications.
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In this lesson, we covered how the
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/etc/services file documents service names and ports.
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Then we talked about the concept of privileged ports.
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Thanks so much for being here
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>> and I look forward to seeing you in the next lesson.
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