svn commit: r44834 - head/en_US.ISO8859-1/books/faq
Dru Lavigne
dru at FreeBSD.org
Wed May 14 21:23:57 UTC 2014
Author: dru
Date: Wed May 14 21:23:56 2014
New Revision: 44834
URL: http://svnweb.freebsd.org/changeset/doc/44834
Log:
Fix some use of "you".
As per discussion at BSDCan, remove section on how to debug a version of
PPP that dumps core.
Sponsored by: iXsystems
Modified:
head/en_US.ISO8859-1/books/faq/book.xml
Modified: head/en_US.ISO8859-1/books/faq/book.xml
==============================================================================
--- head/en_US.ISO8859-1/books/faq/book.xml Wed May 14 20:33:46 2014 (r44833)
+++ head/en_US.ISO8859-1/books/faq/book.xml Wed May 14 21:23:56 2014 (r44834)
@@ -4798,9 +4798,9 @@ ttyvb "/usr/libexec/getty Pc"
<answer>
<para>Use <keycombo
action="simul"><keycap>Ctrl</keycap><keycap>Alt</keycap><keycap>F<replaceable>n</replaceable></keycap></keycombo>
- to switch back to a virtual console. <keycombo
+ to switch back to a virtual console. Press <keycombo
action="simul"><keycap>Ctrl</keycap><keycap>Alt</keycap><keycap>F1</keycap></keycombo>
- would return you to the first virtual console.</para>
+ to return to the first virtual console.</para>
<para>Once at a text console, use
<keycombo
@@ -5194,16 +5194,15 @@ Key F15 A A Menu Wo
<answer>
<para>If the alias is on the same subnet as an address
- already configured on the interface, then add
- <literal>netmask 0xffffffff</literal> to your
- &man.ifconfig.8; command-line, as in the following:</para>
+ already configured on the interface, add
+ <literal>netmask 0xffffffff</literal> to this command:</para>
- <screen>&prompt.root; <userinput>ifconfig ed0 alias 192.0.2.2 netmask 0xffffffff</userinput></screen>
+ <screen>&prompt.root; <userinput>ifconfig <replaceable>ed0</replaceable> alias <replaceable>192.0.2.2 </replaceable>netmask 0xffffffff</userinput></screen>
- <para>Otherwise, just specify the network address and
+ <para>Otherwise, specify the network address and
netmask as usual:</para>
- <screen>&prompt.root; <userinput>ifconfig ed0 alias 172.16.141.5 netmask 0xffffff00</userinput></screen>
+ <screen>&prompt.root; <userinput>ifconfig <replaceable>ed0</replaceable> alias <replaceable>172.16.141.5</replaceable> netmask 0xffffff00</userinput></screen>
<para>More information can be found in the &os; <link
xlink:href="&url.books.handbook;/configtuning-virtual-hosts.html">Handbook</link>.</para>
@@ -5928,7 +5927,7 @@ add 0 0 HISADDR</programlisting>
<answer>
<para>If Link Quality Reporting (<acronym>LQR</acronym>) is configured,
it is possible that too many <acronym>LQR</acronym> packets are lost between
- your machine and the peer. &man.ppp.8; deduces that the
+ the &os; system and the peer. &man.ppp.8; deduces that the
line must therefore be bad, and disconnects. <acronym>LQR</acronym> is
disabled by default and can be enabled with the following
line:</para>
@@ -6013,9 +6012,9 @@ add 0 0 HISADDR</programlisting>
<answer>
<para>There is very little that can be done about this. Many ISPs
will refuse to help users not running a µsoft;
- OS. You can <literal>enable lqr</literal> in
+ OS. Add <literal>enable lqr</literal> to
<filename>/etc/ppp/ppp.conf</filename>, allowing &man.ppp.8; to
- detect the remote failure and hang up, but this detection
+ detect the remote failure and hang up. This detection
is relatively slow and therefore not that useful.</para>
<para>First, try disabling all local compression by adding
@@ -6134,7 +6133,7 @@ deny pred1 deflate deflate24 protocomp a
<para>This tells &man.ppp.8; to wait for the server to
initiate LCP negotiations. Some servers however may never
- initiate negotiations. If this is the case, you can do
+ initiate negotiations. In this case, try
something like:</para>
<programlisting>set openmode active 3</programlisting>
@@ -6207,8 +6206,8 @@ deny pred1 deflate deflate24 protocomp a
<programlisting>set openmode passive</programlisting>
- <para>Care should be taken with this option. You should
- also use this command to limit the amount of time that
+ <para>Care should be taken with this option.
+ This command can also be used to limit the amount of time that
&man.ppp.8; waits for the peer to begin
negotiations:</para>
@@ -6231,14 +6230,13 @@ deny pred1 deflate deflate24 protocomp a
</question>
<answer>
- <para>When you execute the <command>shell</command> or
- <command>!</command> command, &man.ppp.8; executes a shell
- (or if you have passed any arguments, &man.ppp.8; will
- execute those arguments). The
+ <para>When using <command>shell</command> or
+ <command>!</command>, &man.ppp.8; executes a shell
+ or the passed arguments. The
<application>ppp</application> program will wait for the
- command to complete before continuing. If you attempt to
- use the PPP link while running the command, the link will
- appear to have frozen. This is because &man.ppp.8; is
+ command to complete before continuing. Any attempt to
+ use the PPP link while running the command will appear as
+ a frozen link. This is because &man.ppp.8; is
waiting for the command to complete.</para>
<para>To execute commands like this, use
@@ -6275,8 +6273,8 @@ deny pred1 deflate deflate24 protocomp a
</question>
<answer>
- <para>If &man.ppp.8; is dialing unexpectedly, you must
- determine the cause, and set up Dial filters (dfilters) to
+ <para>If &man.ppp.8; is dialing unexpectedly,
+ determine the cause, and set up dial filters to
prevent such dialing.</para>
<para>To determine the cause, use the following line:</para>
@@ -6284,11 +6282,11 @@ deny pred1 deflate deflate24 protocomp a
<programlisting>set log +tcp/ip</programlisting>
<para>This will log all traffic through the connection. The
- next time the line comes up unexpectedly, you will see the
- reason logged with a convenient timestamp next to
+ next time the line comes up unexpectedly, the
+ reason will be logged with a convenient timestamp next to
it.</para>
- <para>You can now disable dialing under these circumstances.
+ <para>Next, disable dialing under these circumstances.
Usually, this sort of problem arises due to DNS lookups.
To prevent DNS lookups from establishing a connection
(this will <emphasis>not</emphasis> prevent &man.ppp.8;
@@ -6300,31 +6298,29 @@ set dfilter 2 deny udp dst eq 53
set dfilter 3 permit 0/0 0/0</programlisting>
<para>This is not always suitable, as it will effectively
- break your demand-dial capabilities — most programs
+ break demand-dial capabilities. Most programs
will need a DNS lookup before doing any other network
related things.</para>
- <para>In the DNS case, you should try to determine what is
+ <para>In the DNS case, try to determine what is
actually trying to resolve a host name. A lot of the
- time, &man.sendmail.8; is the culprit. You should make
- sure that you tell <application>sendmail</application> not
+ time, &man.sendmail.8; is the culprit. Make
+ sure to configure <application>sendmail</application> not
to do any DNS lookups in its configuration file. See the
section on <link
xlink:href="&url.books.handbook;/smtp-dialup.html">using
email with a dialup connection</link> in the &os;
- Handbook for details on how to create your own
- configuration file and what should go into it. You may
+ Handbook for details. You may
also want to add the following line to
<filename>.mc</filename>:</para>
<programlisting>define(`confDELIVERY_MODE', `d')dnl</programlisting>
<para>This will make <application>sendmail</application>
- queue everything until the queue is run (usually, sendmail
- is run with <option>-bd -q30m</option>, telling it to run
- the queue every 30 minutes) or until a <command>sendmail
- -q</command> is done (perhaps from your
- <filename>ppp.linkup</filename>).</para>
+ queue everything until the queue is run, usually,
+ every 30 minutes, or until a <command>sendmail
+ -q</command> is done, perhaps from
+ <filename>/etc/ppp/ppp.linkup</filename>.</para>
</answer>
</qandaentry>
@@ -6343,8 +6339,7 @@ CCP: Received Terminate Ack (1) state =
<para>This is because &man.ppp.8; is trying to negotiate
Predictor1 compression, and the peer does not want to
negotiate any compression at all. The messages are
- harmless, but if you wish to remove them, you can disable
- Predictor1 compression locally too:</para>
+ harmless, but can be disabled with:</para>
<programlisting>disable pred1</programlisting>
</answer>
@@ -6357,8 +6352,8 @@ CCP: Received Terminate Ack (1) state =
</question>
<answer>
- <para>To log all lines of your modem
- <quote>conversation</quote>, you must enable the
+ <para>To log all lines of the modem
+ conversation, enable the
following:</para>
<programlisting>set log +connect</programlisting>
@@ -6366,18 +6361,16 @@ CCP: Received Terminate Ack (1) state =
<para>This will make &man.ppp.8; log everything up until the
last requested <quote>expect</quote> string.</para>
- <para>If you wish to see your connect speed and are using
- PAP or CHAP (and therefore do not have anything to
- <quote>chat</quote> after the CONNECT in the dial script
- — no <literal>set login</literal> script), you must
- make sure that you instruct &man.ppp.8; to
- <quote>expect</quote> the whole CONNECT line, something
+ <para>To seether connect speed when using
+ PAP or CHAP,
+ make sure to configure &man.ppp.8; to
+ expect the whole CONNECT line, using something
like this:</para>
<programlisting>set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 4 \
\"\" ATZ OK-ATZ-OK ATDT\\T TIMEOUT 60 CONNECT \\c \\n"</programlisting>
- <para>Here, we get our CONNECT, send nothing, then expect a
+ <para>This gets the CONNECT, sends nothing, then expects a
line-feed, forcing &man.ppp.8; to read the whole CONNECT
response.</para>
</answer>
@@ -6391,22 +6384,22 @@ CCP: Received Terminate Ack (1) state =
<answer>
<para>The <application>ppp</application> utility parses each
- line in your config files so that it can interpret strings
+ line in its configuration files so that it can interpret strings
such as <literal>set phone "123 456 789"</literal>
correctly and realize that the number is actually only
- <emphasis>one</emphasis> argument. To specify a
- <literal>"</literal> character, you must escape it
+ one argument. To specify a
+ <literal>"</literal> character, escape it
using a backslash (<literal>\</literal>).</para>
<para>When the chat interpreter parses each argument, it
re-interprets the argument to find any special escape
sequences such as <literal>\P</literal> or
- <literal>\T</literal> (see the manual page). As a result
- of this double-parsing, you must remember to use the
+ <literal>\T</literal>. As a result
+ of this double-parsing, remember to use the
correct number of escapes.</para>
- <para>If you wish to actually send a <literal>\</literal>
- character to (say) your modem, you would need something
+ <para>To actually send a <literal>\</literal>
+ character, do something
like:</para>
<programlisting>set dial "\"\" ATZ OK-ATZ-OK AT\\\\X OK"</programlisting>
@@ -6432,136 +6425,6 @@ ATDT1234567</programlisting>
</qandaentry>
<qandaentry>
- <question xml:id="ppp-segfault-nocore">
- <para>Why does &man.ppp.8; get a <errorname>Segmentation
- fault</errorname>, but I see no
- <filename>ppp.core</filename></para>
- </question>
-
- <answer>
- <para>The <application>ppp</application> utility (or any
- other program for that matter) should never dump core.
- Because &man.ppp.8; runs setuid (with an effective
- user ID of <literal>0</literal>), the operating
- system will not write core image of &man.ppp.8; to disk
- before terminating it. If, however &man.ppp.8; is
- actually terminating due to a segmentation violation or
- some other signal that normally causes core to be dumped,
- <emphasis>and</emphasis> you are sure you are using the
- latest version (see the start of this section), then you
- should install the system sources and do the
- following:</para>
-
- <screen>&prompt.root; <userinput>cd /usr/src/usr.sbin/ppp</userinput>
-&prompt.root; <userinput>echo STRIP= >> /etc/make.conf</userinput>
-&prompt.root; <userinput>echo CFLAGS+=-g >> /etc/make.conf</userinput>
-&prompt.root; <userinput>make install clean</userinput></screen>
-
- <para>You will now have a debuggable version of &man.ppp.8;
- installed. You will have to be <systemitem
- class="username">root</systemitem> to run &man.ppp.8; as
- all of its privileges have been revoked. When you start
- &man.ppp.8;, take a careful note of what your current
- directory was at the time.</para>
-
- <para>Now, if and when &man.ppp.8; receives the segmentation
- violation, it will dump a core file called
- <filename>ppp.core</filename>. You should then do the
- following:</para>
-
- <screen>&prompt.user; <userinput>su</userinput>
-&prompt.root; <userinput>gdb /usr/sbin/ppp ppp.core</userinput>
-<prompt>(gdb)</prompt> <userinput>bt</userinput>
-.....
-<prompt>(gdb)</prompt> <userinput>f 0</userinput>
-....
-<prompt>(gdb)</prompt> <userinput>i args</userinput>
-....
-<prompt>(gdb)</prompt> <userinput>l</userinput>
-.....</screen>
-
- <para>All of this information should be given alongside your
- question, making it possible to diagnose the
- problem.</para>
-
- <para>If you are familiar with &man.gdb.1;, you may wish to
- find out some other bits and pieces such as what actually
- caused the dump or the addresses and values of the
- relevant variables.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-autodialprocess-noconnect">
- <para>Why does the process that forces a dial in
- <option>-auto</option> mode never connect?</para>
- </question>
-
- <answer>
- <para>This was a known problem with &man.ppp.8; set up to
- negotiate a dynamic local IP number with the peer in
- <option>-auto</option> mode. It has been fixed a long
- time ago — search the manual page for
- <literal>iface</literal>.</para>
-
- <para>The problem was that when that initial program calls
- &man.connect.2;, the IP number of the &man.tun.4;
- interface is assigned to the socket endpoint. The kernel
- creates the first outgoing packet and writes it to the
- &man.tun.4; device. &man.ppp.8; then reads the packet and
- establishes a connection. If, as a result of
- &man.ppp.8;'s dynamic IP assignment, the interface address
- is changed, the original socket endpoint will be invalid.
- Any subsequent packets sent to the peer will usually be
- dropped. Even if they are not, any responses will not
- route back to the originating machine as the IP number is
- no longer owned by that machine.</para>
-
- <para>There are several theoretical ways to approach this
- problem. It would be nicest if the peer would re-assign
- the same IP number if possible. The current version of
- &man.ppp.8; does this, but most other implementations do
- not.</para>
-
- <para>The easiest method from our side would be to never
- change the &man.tun.4; interface IP number, but instead to
- change all outgoing packets so that the source IP number
- is changed from the interface IP to the negotiated IP on
- the fly. This is essentially what the
- <literal>iface-alias</literal> option in the latest
- version of &man.ppp.8; is doing (with the help of
- &man.libalias.3; and &man.ppp.8;'s <option>-nat</option>
- switch) — it is maintaining all previous interface
- addresses and NATing them to the last negotiated
- address.</para>
-
- <para>Another alternative (and probably the most reliable)
- would be to implement a system call that changes all bound
- sockets from one IP to another. &man.ppp.8; would use
- this call to modify the sockets of all existing programs
- when a new IP number is negotiated. The same system call
- could be used by <acronym>DHCP</acronym> clients when they
- are forced to call the <function>bind()</function>
- function for their sockets.</para>
-
- <para>Yet another possibility is to allow an interface to be
- brought up without an IP number. Outgoing packets would
- be given an IP number of <systemitem
- class="ipaddress">255.255.255.255</systemitem> up until
- the first <literal>SIOCAIFADDR</literal> &man.ioctl.2; is
- done. This would result in fully binding the socket. It
- would be up to &man.ppp.8; to change the source IP number,
- but only if it is set to <systemitem
- class="ipaddress">255.255.255.255</systemitem>, and only
- the IP number and IP checksum would need to change. This,
- however is a bit of a hack as the kernel would be sending
- bad packets to an improperly configured interface, on the
- assumption that some other mechanism is capable of fixing
- things retrospectively.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
<question xml:id="ppp-nat-games">
<para>Why do most games not work with the
<option>-nat</option> switch?</para>
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