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Diffstat (limited to 'chapter_16.xml')
| -rw-r--r-- | chapter_16.xml | 419 |
1 files changed, 397 insertions, 22 deletions
diff --git a/chapter_16.xml b/chapter_16.xml index 484ede3..97a0fee 100644 --- a/chapter_16.xml +++ b/chapter_16.xml @@ -13,7 +13,7 @@ chapter is for you. </para> <section id="network-utils_network-diagnostics"> -<title>Network Diagnostic Tools</title> + <title>Network Diagnostic Tools</title> <para> Slackware Linux includes a great many networking tools for @@ -158,7 +158,7 @@ every Linux, UNIX, and BSD distribution today makes use of OpenSSH, or commonly used network tools today and makes use of the strongest cryptographic techniques. <application>ssh</application> has many features, configuration options, and neat hacks, enough to fill its own -book, so we'll only go into the basics here. Simply run +book, so we'll only go into the basics here. Simply run <application>ssh</application> with the user name and the host and you'll be connected to it quickly and safely. If this is the first time you are connecting to this computer, <application>ssh</application> @@ -169,7 +169,8 @@ because it is possible that some one is attempting to hijack the connection using what is known as a man-in-the-middle attack. </para> -<screen><prompt>darkstar:~# </prompt><userinput>ssh alan@slackware.com</userinput> +<screen> +<prompt>darkstar:~# </prompt><userinput>ssh alan@slackware.com</userinput> alan@slackware.com's password: <userinput>secret</userinput> <prompt>alan@slackware.com:~$ </prompt> </screen> @@ -180,10 +181,13 @@ If you leave off the username part, <application>ssh</application> will use your current username when establishing the connection. </para> +<!-- add stuff about ssh keys --> +<!-- add stuff about scp --> + </section> -<section> -<title>tcpdump</title> +<section id="network-utils_tcpdump"> + <title>tcpdump</title> <para> So far all the tools we've looked at have focused on making connections @@ -232,6 +236,9 @@ each one individually, <application>telnet</application> to each port you're interested in, and note every detail, but that's very tedious and time consuming. A much easier alternative is to use a port scanner, and <application>nmap</application>(1) is just the tool for the job. +</para> + +<para> <application>nmap</application> is capable of scanning TCP and UDP ports, determining the operating system of a network device, probing each located service to determine its specific type, and much much @@ -301,7 +308,7 @@ slackware.com mail is handled by 1 mail-mx.cwo.com. </section> -<section> +<section id="network-utils_dig"> <title>dig</title> <para> @@ -353,7 +360,8 @@ In this case we looked for an "A" record which returned an IPv4 address. </section> -<section><title>finger</title> +<section id="network-utils_finger"> +<title>finger</title> <para> <application>finger</application>(1) isn't exactly a network diagnostic @@ -387,7 +395,7 @@ No Plan. </section> <section id="network-utils_web-browsers"> -<title>Web Browsers</title> + <title>Web Browsers</title> <para> Slackware includes a variety of web browsers. If you're using a @@ -436,7 +444,8 @@ formats web pages better. </section> -<section><title>wget</title> +<section id="network-utils_wget"> + <title>wget</title> <para> Unlike the other browsers we've looked at, @@ -477,7 +486,18 @@ Length: 75306 (74K) <section id="network-utils_mail-clients"> <title>Mail Clients</title> -<section><title>pine</title> +<para> +Slackware also includes a variety of email clients. If you're using a +graphical desktop, you'll find <application>Thunderbird</application>, +<application>Kmail</application>, <application>sylpheed</application> +and others. As with web browsers, there are also applications that +function within the shell. Once you start using an email client in the +console, you may find yourself not wanting to use anything else; the +flexibility and configurability can be addicting. +</para> + +<section id="network-utils_pine"> +<title>pine</title> <para> <application>pine</application> is one of the oldest command-line @@ -494,7 +514,7 @@ pine-clone distributed with Slackware, was born. To start using <application>alpine</application>, simply type <application>pine</application> at the command line. Using it is very simple due to its menu-driven system as well as the -command referance neatly located at the bottom of the screen. See for +command reference neatly located at the bottom of the screen. See for yourself: </para> @@ -524,6 +544,106 @@ Messages O OTHER CMDS > [ListFldrs] N NextCmd K KBLock </screen> + <para> + Before configuring any mail client, you should check the + documentation of your mail server to gather all of the pertinent + information about what protocols and security measures your mail + service uses. This will help you configure + <application>pine</application> correctly. +</para> + + <para> + To start configuring <application>pine</application>, you should be + able to enter the [S]ettings menu, and then the [C]onfig + screen. There are about a hundred different options, but the most + common and most important ones would be your Personal Name, Inbox + Path, and SMTP Server. +</para> + +<variablelist> + <title>Pine Settings</title> + + <varlistentry> + <term> + Personal Name + </term> + <listitem> + <para> + The name you wish people to see in the "From" field of your + emails. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + Inbox Path + </term> + + <listitem> + <para> + Your mail server. The server itself is often something like + mail.example.com (although it may not be; check with your + host to be sure), but if that server requires login information then you + may need to set it to something like alan@mail.slackermedia.info + or similar. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>SMTP Server</term> + <listitem> + <para> + The server through which you will send your email; often this + is smtp.example.com or outgoing.example.com or some variation + on that theme. It often requires authentication, but you + should be prompted for this in + <application>pine</application> when sending mail. + </para> + </listitem> + </varlistentry> +</variablelist> + +<para> + A sample configuration might look a little something like this: +</para> + +<table> + <title>Sample Pine Configuration</title> + <tgroup cols="2"> + <tbody> + <row> + <entry>Personal Name</entry> + <entry>Alan Hicks</entry> + </row> + <row> + <entry>SMTP Server</entry> + <entry>smtp.lizella.net</entry> + </row> + <row> + <entry>Inbox Path</entry> + <entry>{imap.lizella.net/user=alan@lizella.net}inbox</entry> + </row> + <row> + <entry>Warn if Blank Subject</entry> + <entry>X</entry> + </row> + <row> + <entry>Sort Key: Arrival</entry> + <entry>X</entry> + </row> + </tbody> + </tgroup> +</table> + +<para> + And so on. Once you have it configured according to your mail + server's settings, you will be able to navigate the application from + the main menu. It's quite intuitive, with a persistent list of + keyboard shortcuts at the bottom of the screen. +</para> + </section> <section id="network-utils_mutt"> @@ -535,7 +655,7 @@ want more control. Some people want a fully-configurable mail client with plugin support and a no-nonsense attitude. Those people use <application>mutt</application>(1). <application>mutt</application> isn't as user friendly as <application>pine</application>, but makes up -for it with power. You won't find the user-friendly command referance +for it with power. You won't find the user-friendly command reference at the bottom of the screen, <application>mutt</application> uses every last inch of real-estate for mail processing duty. It's feature support is extensive: threaded displays are no problem for the mighty @@ -562,14 +682,266 @@ for that, muttrc(5). You might want to read up on it. 3185 N Jan 11 Robby Workman (3.4K) └─> 3186 N Jan 12 SlackBuilds@cat (3.4K) └─> 3187 N Jan 11 Robby Workman (4.5K) └─> -3188 N Jan 12 Robby Workman (2.3K) [Slackbuilds-users] Unavailability of mai -3189 N Jan 13 Mr. B-o-B (3.7K) └─> -3190 N Jan 13 Josiah Boothby (3.2K) [Slackbuilds-users] Ted's Word Processor -3191 N Jan 14 Adam Swift (7.4K) [Slackbuilds-users] Web submission failur -3192 N Jan 14 Rob McGee (3.5K) └─> +3188 D Jan 12 Klaatu (3.5K) [Slackbuilds-users] LiVES updates +3189 N Jan 12 Robby Workman (2.3K) [Slackbuilds-users] Unavailability of mai +3190 N Jan 13 Mr. B-o-B (3.7K) └─> +3191 N Jan 13 Josiah Boothby (3.2K) [Slackbuilds-users] Ted's Word Processor +3192 N Jan 14 Adam Swift (7.4K) [Slackbuilds-users] Web submission failur +3193 N Jan 14 Rob McGee (3.5K) └─> </screen> -</section> +<para> + Using <application>mutt</application> is unique because it is by + nature a Mail User Agent (MUA), meaning its true purpose is to read + and sort email. This was its only job originally, although some + additional features such as retrieving mail via POP3 and even very + basic transfering messages via SMTP have snuck into the application. +</para> + +<para> + As is so often the case with robust console-based applications, the + configuration options are myriad, and there is no "right" or + "wrong" way of using <application>mutt</application> as long + as it does what you want it to do. Here is a simple example of a + system utilizing <application>mutt</application>, with a toolchain + consisting of: +</para> + +<itemizedlist> + <listitem> + <para> + <application>fetchmail</application> to pull mail from your mail server + via POP3 + </para> +</listitem> + + <listitem> + <para> + <application>procmail</application> to sort the mail as needed. + </para> + </listitem> + + <listitem> + <para> + <application>mutt</application> to read, sort, and send email. + </para> +</listitem> + + <listitem> + <para> + <command>formail</command> to re-format your mail if needed + (depending on your mail server settings) + </para> +</listitem> +</itemizedlist> + +<para> + <application>fetchmail</application> is a simple application that exists + only to pull mail from mail servers and copy those email messages to + your local hard drive. The configuration is fairly simple: +</para> + +<screen> + <prompt>darkstar:~$ </prompt> 'poll pop.slackermedia.info with proto pop3: user +"klaatu@slackermedia.info" there has password "secretpassword" is klaatu +here and wants mds "/usr/bin/procmail"' >> ~/.fetchmailrc +</screen> + +<variablelist> +<title>Fetchmail Configuration Explained</title> + +<varlistentry> + <term>poll</term> + <listitem> + <para> + Defines the mail server to check + </para> + </listitem> +</varlistentry> + +<varlistentry> + <term>with proto</term> + <listitem> + <para> + Defines the protocol used; in this case, POP3. + </para> + </listitem> +</varlistentry> + +<varlistentry> + <term>user</term> + <listitem> + <para> + Your email username. Sometimes this is just the string in front + of the @ at symbol, othertimes it is your whole email address. + Again, see your provider's documentation to find out what + you should be using. + </para> + </listitem> +</varlistentry> + +<varlistentry> + <term>there has password</term> + + <listitem> + <para> + Your email password. This is entered as plaintext into your + config file, but since this is in your home directory, it is only + readable by you. + </para> + </listitem> +</varlistentry> + +<varlistentry> + <term>is username here</term> + <listitem> + <para> + Defines which user on your local computer this email account + actually belongs to. For instance, if my email account is + notklaatu@slackermedia.info but my username on my Slackware box + is klaatu, then obviously there would be no way for + <application>fetchmail</application> to know who + notklaatu@slackermedia.info is. This defines it. + </para> + </listitem> +</varlistentry> + +<varlistentry> + <term>and wants mda "/usr/bin/procmail"</term> + + <listitem> + <para> + Tells <application>fetchmail</application> what application will + be sorting the email once it is pulled from the mail server. + <application>Procmail</application> ships with Slackware, so this + will probably not change for you and is not dependent upon your + mail server whatsoever. + </para> + </listitem> +</varlistentry> +</variablelist> + +<para> + Now that fetchmail is configured, it will successfully pull your + email from the server. But what will your computer do with all of + that mail? This is the job of <application>procmail</application>. +</para> + +<para> + The settings for <application>procmail</application> can be stored + in ~/.procmailrc and is also fairly simple; for example: +</para> + +<screen> + PATH=/usr/bin + MAILDIR=$HOME/Mail + DEFAULT=$MAILDIR/Inbox + LOGFILE=$MAILDIR/logs +</screen> + +<para> + Now <application>procmail</application> is configured, so your mail + will be sent to the right place. There is much more you can do with + <application>procmail</application> so feel free to investigate its + many filtering functions (or "recipes") later, once you have + everything working. +</para> + +<para> + At this point, your email will be pulled from the server by + <application>fetchmail</application> and sorted on your local system + by way of <application>procmail</application>. You need to + configure <application>mutt</application> so that it knows where to + find your email messages so that you can view them. +</para> + +<para> + Because <application>mutt</application> is such an extensible program, it's + a good idea to make a folder for its configuration file. Your + initial configuration will be frightfully simple, but if you ever + look for new configurations of mutt you might be happy to have a + whole folder to play around in. +</para> + + <screen> + <prompt>darkstar:~$ </prompt> <command>cat</command> ~/.mutt/.muttrc + set realname="klaatu" + set from="notklaatu@slackermedia.info" + set spoolfile=/home/klaatu/Mail/Inbox + set mbox=/home/klaatu/Mail/mbox + set record=/home/klaatu/Mail/sent + set postponed=/home/klaatu/Mail/postponed + set sort=reverse-date + set editor=emacs + set smtp_url="smtp://notklaatu:secretpassword@smtp.slackermedia.info:465" + </screen> + +<para> + In this sample configuration, the <varname>spoolfile</varname> + defines the incoming messages that you have not read yet (you + might recognize it as the end destination for + <application>procmail</application>), while <varname>mbox</varname> + defines where mail that you have read and responded to will be + stored. All other settings are self-explanatory, and all have been + drawn directly from the muttrc man page. +</para> + +<note> +<para> + If your mail server delivers your email in a format that + <command>mutt</command> cannot understand, use the + <application>formail</application> mailbox converter, a part of the + <application>procmail</application> distribution. For example: +</para> + +<screen> + <prompt>darkstar:~$ </prompt> formail -ds < ~/Mail/Inbox >> ~/Mail/Muttbox + </screen> +</note> + + +<para> + The commands used to navigate around in <application>mutt</application> are highly + customizable but the defaults can be listed by typing + <keycap>?</keycap>. +</para> + +<section id="network-utils_ssl"> + <title>Adding SSL Support</title> + + <para> + If your mail server supports SSL then you can and should use SSL + for better security. Most graphical clients have common SSL + certificates built into them; <application>mutt</application> does + not but it's trivial to configure. + </para> + + <para> + Download an SSL trust certificate (the most common set is from + Thawte) and place it in your Mutt or Mail folder, and list it + as a <varname>certificate_file</varname> in your + <filename>.muttrc</filename> file. If your mail server is not using + Thawte, then they may be using either another SSL certificate + authority or they may be their own certificate authority, but + if an unknown certificate is encountered, + <application>mutt</application> will prompt you to accept it (or + not). If you do accept it, the certificate can be saved into + this certificate file. + </para> + + <para> + To obtain the Thawte certificate: + </para> + + <screen> + bash$ wget + http://www.thawte.com/roots/thawte_Premium_Server_CA.pem -P + ~/Mail/ + </screen> + +</section> <!-- closing SSL --> + +</section> <!-- closing mutt --> <section id="network-utils_mailx"> <title>mailx</title> @@ -708,7 +1080,8 @@ downloaded in source code or binary form via FTP, so knowing how to retrieve this information is a handy skill. </para> -<section><title>ftp</title> +<section id="network-utils_bsd-ftp"> +<title>ftp</title> <para> The simplest FTP client included with Slackware is named simply, @@ -753,7 +1126,8 @@ ftp> <userinput>bye</userinput> </section> -<section><title>ncftp</title> +<section id="network-utils_ncftp"> +<title>ncftp</title> <para> <application>ncftp</application>(1) (pronounced nick-f-t-p), is a more @@ -788,7 +1162,8 @@ ncftp ...ware/slackware-current > <userinput>bye</userinput> </section> -<section><title>lftp</title> +<section id="network-utils_lftp"> +<title>lftp</title> <para> The last client we're going to look at is @@ -815,7 +1190,7 @@ lftp ftp.osuosl.org:/pub/slackware/slackware-current> <userinput>bye</userinput> </section> -<section> +<section id="network-utils_rsync"> <title>rsync</title> <para> |