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diff --git a/Master/tlpkg/tlperl/lib/Net/libnetFAQ.pod b/Master/tlpkg/tlperl/lib/Net/libnetFAQ.pod new file mode 100644 index 00000000000..78efe8c44bb --- /dev/null +++ b/Master/tlpkg/tlperl/lib/Net/libnetFAQ.pod @@ -0,0 +1,302 @@ +=head1 NAME + +libnetFAQ - libnet Frequently Asked Questions + +=head1 DESCRIPTION + +=head2 Where to get this document + +This document is distributed with the libnet distribution, and is also +available on the libnet web page at + + http://search.cpan.org/dist/libnet/ + +=head2 How to contribute to this document + +You may report corrections, additions, and suggestions on the +CPAN request tracker at + + http://rt.cpan.org/Dist/Display.html?Name=libnet + +=head1 Author and Copyright Information + +Copyright (c) 1997-1998 Graham Barr. All rights reserved. +This document is free; you can redistribute it and/or modify it +under the terms of the Artistic License. + +Currently maintained by Steve Hay <shay@cpan.org>. + +=head2 Disclaimer + +This information is offered in good faith and in the hope that it may +be of use, but is not guaranteed to be correct, up to date, or suitable +for any particular purpose whatsoever. The authors accept no liability +in respect of this information or its use. + + +=head1 Obtaining and installing libnet + +=head2 What is libnet ? + +libnet is a collection of perl5 modules which all related to network +programming. The majority of the modules available provided the +client side of popular server-client protocols that are used in +the internet community. + +=head2 Which version of perl do I need ? + +libnet has been know to work with versions of perl from 5.002 onwards. However +if your release of perl is prior to perl5.004 then you will need to +obtain and install the IO distribution from CPAN. If you have perl5.004 +or later then you will have the IO modules in your installation already, +but CPAN may contain updates. + +=head2 What other modules do I need ? + +The only modules you will need installed are the modules from the IO +distribution. If you have perl5.004 or later you will already have +these modules. + +=head2 What machines support libnet ? + +libnet itself is an entirely perl-code distribution so it should work +on any machine that perl runs on. However IO may not work +with some machines and earlier releases of perl. But this +should not be the case with perl version 5.004 or later. + +=head2 Where can I get the latest libnet release + +The latest libnet release is always on CPAN, you will find it +in + + http://search.cpan.org/dist/libnet/ + +=head1 Using Net::FTP + +=head2 How do I download files from an FTP server ? + +An example taken from an article posted to comp.lang.perl.misc + + #!/your/path/to/perl + + # a module making life easier + + use Net::FTP; + + # for debugging: $ftp = Net::FTP->new('site','Debug',10); + # open a connection and log in! + + $ftp = Net::FTP->new('target_site.somewhere.xxx'); + $ftp->login('username','password'); + + # set transfer mode to binary + + $ftp->binary(); + + # change the directory on the ftp site + + $ftp->cwd('/some/path/to/somewhere/'); + + foreach $name ('file1', 'file2', 'file3') { + + # get's arguments are in the following order: + # ftp server's filename + # filename to save the transfer to on the local machine + # can be simply used as get($name) if you want the same name + + $ftp->get($name,$name); + } + + # ftp done! + + $ftp->quit; + +=head2 How do I transfer files in binary mode ? + +To transfer files without <LF><CR> translation Net::FTP provides +the C<binary> method + + $ftp->binary; + +=head2 How can I get the size of a file on a remote FTP server ? + +=head2 How can I get the modification time of a file on a remote FTP server ? + +=head2 How can I change the permissions of a file on a remote server ? + +The FTP protocol does not have a command for changing the permissions +of a file on the remote server. But some ftp servers may allow a chmod +command to be issued via a SITE command, eg + + $ftp->quot('site chmod 0777',$filename); + +But this is not guaranteed to work. + +=head2 Can I do a reget operation like the ftp command ? + +=head2 How do I get a directory listing from an FTP server ? + +=head2 Changing directory to "" does not fail ? + +Passing an argument of "" to ->cwd() has the same affect of calling ->cwd() +without any arguments. Turn on Debug (I<See below>) and you will see what is +happening + + $ftp = Net::FTP->new($host, Debug => 1); + $ftp->login; + $ftp->cwd(""); + +gives + + Net::FTP=GLOB(0x82196d8)>>> CWD / + Net::FTP=GLOB(0x82196d8)<<< 250 CWD command successful. + +=head2 I am behind a SOCKS firewall, but the Firewall option does not work ? + +The Firewall option is only for support of one type of firewall. The type +supported is an ftp proxy. + +To use Net::FTP, or any other module in the libnet distribution, +through a SOCKS firewall you must create a socks-ified perl executable +by compiling perl with the socks library. + +=head2 I am behind an FTP proxy firewall, but cannot access machines outside ? + +Net::FTP implements the most popular ftp proxy firewall approach. The scheme +implemented is that where you log in to the firewall with C<user@hostname> + +I have heard of one other type of firewall which requires a login to the +firewall with an account, then a second login with C<user@hostname>. You can +still use Net::FTP to traverse these firewalls, but a more manual approach +must be taken, eg + + $ftp = Net::FTP->new($firewall) or die $@; + $ftp->login($firewall_user, $firewall_passwd) or die $ftp->message; + $ftp->login($ext_user . '@' . $ext_host, $ext_passwd) or die $ftp->message. + +=head2 My ftp proxy firewall does not listen on port 21 + +FTP servers usually listen on the same port number, port 21, as any other +FTP server. But there is no reason why this has to be the case. + +If you pass a port number to Net::FTP then it assumes this is the port +number of the final destination. By default Net::FTP will always try +to connect to the firewall on port 21. + +Net::FTP uses IO::Socket to open the connection and IO::Socket allows +the port number to be specified as part of the hostname. So this problem +can be resolved by either passing a Firewall option like C<"hostname:1234"> +or by setting the C<ftp_firewall> option in Net::Config to be a string +in the same form. + +=head2 Is it possible to change the file permissions of a file on an FTP server ? + +The answer to this is "maybe". The FTP protocol does not specify a command to change +file permissions on a remote host. However many servers do allow you to run the +chmod command via the C<SITE> command. This can be done with + + $ftp->site('chmod','0775',$file); + +=head2 I have seen scripts call a method message, but cannot find it documented ? + +Net::FTP, like several other packages in libnet, inherits from Net::Cmd, so +all the methods described in Net::Cmd are also available on Net::FTP +objects. + +=head2 Why does Net::FTP not implement mput and mget methods + +The quick answer is because they are easy to implement yourself. The long +answer is that to write these in such a way that multiple platforms are +supported correctly would just require too much code. Below are +some examples how you can implement these yourself. + +sub mput { + my($ftp,$pattern) = @_; + foreach my $file (glob($pattern)) { + $ftp->put($file) or warn $ftp->message; + } +} + +sub mget { + my($ftp,$pattern) = @_; + foreach my $file ($ftp->ls($pattern)) { + $ftp->get($file) or warn $ftp->message; + } +} + + +=head1 Using Net::SMTP + +=head2 Why can't the part of an Email address after the @ be used as the hostname ? + +The part of an Email address which follows the @ is not necessarily a hostname, +it is a mail domain. To find the name of a host to connect for a mail domain +you need to do a DNS MX lookup + +=head2 Why does Net::SMTP not do DNS MX lookups ? + +Net::SMTP implements the SMTP protocol. The DNS MX lookup is not part +of this protocol. + +=head2 The verify method always returns true ? + +Well it may seem that way, but it does not. The verify method returns true +if the command succeeded. If you pass verify an address which the +server would normally have to forward to another machine, the command +will succeed with something like + + 252 Couldn't verify <someone@there> but will attempt delivery anyway + +This command will fail only if you pass it an address in a domain +the server directly delivers for, and that address does not exist. + +=head1 Debugging scripts + +=head2 How can I debug my scripts that use Net::* modules ? + +Most of the libnet client classes allow options to be passed to the +constructor, in most cases one option is called C<Debug>. Passing +this option with a non-zero value will turn on a protocol trace, which +will be sent to STDERR. This trace can be useful to see what commands +are being sent to the remote server and what responses are being +received back. + + #!/your/path/to/perl + + use Net::FTP; + + my $ftp = new Net::FTP($host, Debug => 1); + $ftp->login('gbarr','password'); + $ftp->quit; + +this script would output something like + + Net::FTP: Net::FTP(2.22) + Net::FTP: Exporter + Net::FTP: Net::Cmd(2.0801) + Net::FTP: IO::Socket::INET + Net::FTP: IO::Socket(1.1603) + Net::FTP: IO::Handle(1.1504) + + Net::FTP=GLOB(0x8152974)<<< 220 imagine FTP server (Version wu-2.4(5) Tue Jul 29 11:17:18 CDT 1997) ready. + Net::FTP=GLOB(0x8152974)>>> user gbarr + Net::FTP=GLOB(0x8152974)<<< 331 Password required for gbarr. + Net::FTP=GLOB(0x8152974)>>> PASS .... + Net::FTP=GLOB(0x8152974)<<< 230 User gbarr logged in. Access restrictions apply. + Net::FTP=GLOB(0x8152974)>>> QUIT + Net::FTP=GLOB(0x8152974)<<< 221 Goodbye. + +The first few lines tell you the modules that Net::FTP uses and their versions, +this is useful data to me when a user reports a bug. The last seven lines +show the communication with the server. Each line has three parts. The first +part is the object itself, this is useful for separating the output +if you are using multiple objects. The second part is either C<<<<<> to +show data coming from the server or C<>>>>> to show data +going to the server. The remainder of the line is the command +being sent or response being received. + +=head1 AUTHOR AND COPYRIGHT + +Copyright (c) 1997 Graham Barr. +All rights reserved. + |