Managing Linux Systems with Webmin System Administration and Module Development

by Cameron, Jamie

• ISBN13: 9780131408821
• ISBN10: 0131408828
• Edition: 1st
• Format: Paperback
• Copyright: 2003-08-05
• Publisher: Prentice Hall
• More Book Details
• Purchase Benefits

Summary

bull; Written by the creator of Webmin -- the most popular GUI admin tool for Linux bull; Webmin is currently downloaded 4000 times a day & -- nearly one million times of all versions in the last year! Shows how to use Webmin to configure Apache, Sendmail, and other complex Linux servers bull; Start developing your own Webmin modules and themes with the complete reference for the API

Author Biography

Jamie Cameron, Webmin's primary developer, has unsurpassed knowledge of Webmin's functions, user interface, and internal design. He has been working with and managing UNIX and Linux systems for over seven years

Table of Contents

1 Introduction to Webmin	1	(5)
What is Webmin?	1	(1)
Who Should Use Webmin?	2	(1)
How and Why Was it Developed?	3	(1)
What is this Book About?	4	(1)
Who Should Read this Book?	4	(1)
Conventions Used in this Book	5	(1)
Acknowledgments	5	(1)
2 Installing Webmin	6	(8)
Downloading Webmin for Your System	6	(1)
Installing the RPM Package	7	(1)
Installing the tar.gz Package	8	(2)
Installing the Solaris Package	10	(1)
The Webmin User Interface	10	(3)
Uninstalling Webmin	13	(1)
Summary	13	(1)
3 Securing Your Webmin Server	14	(5)
Network Security	14	(1)
SSL Encryption	15	(2)
Requesting a Valid SSL Certificate	17	(1)
Summary	18	(1)
4 Users and Groups	19	(20)
Introduction to UNIX Users and Groups	19	(1)
The Users and Groups Module	20	(1)
Creating a New User	21	(2)
Editing an Existing User	23	(1)
Deleting a User	24	(1)
Creating a New Group	25	(1)
Editing an Existing Group	26	(1)
Deleting a Group	27	(1)
Viewing Recent and Current Logins	27	(1)
Reading Users' Email	28	(1)
Creating Users from Batch Files	28	(2)
Configuring the Users and Groups Module	30	(4)
Before and After Commands	34	(1)
Module Access Control	34	(3)
Other Operating Systems	37	(1)
Summary	38	(1)
5 Disk and Network Filesystems	39	(14)
Introduction to Filesystems	39	(1)
The Disk and Network Filesystems Module	40	(1)
Mounting an NFS Network Filesystem	40	(3)
Mounting an SMBFS Windows Networking Filesystem	43	(1)
Mounting a Local ext2 or ext3 Hard Disk Filesystem	44	(1)
Mounting a Local Windows Hard Disk Filesystem	45	(1)
Adding Virtual Memory	46	(1)
Automounter Filesystems	47	(1)
Editing or Removing an Existing Filesystem	48	(1)
Listing Users of a Filesystem	48	(1)
Module Access Control	49	(1)
Configuring the Disk and Network Filesystems Module	50	(1)
A Comparison of Filesystem Types	50	(1)
Other Operating Systems	51	(1)
Summary	52	(1)
6 NFS File Sharing	53	(7)
Introduction to File Sharing with NFS	53	(1)
The NFS Exports Module	54	(1)
Exporting a Directory	54	(1)
Editing or Deleting an NFS Export	55	(1)
NFS on Solaris	56	(1)
NFS on BSD, MacOS X and OpenServer	57	(2)
NFS on Irix	59	(1)
Summary	59	(1)
7 Disk Quotas	60	(8)
Introduction to Disk Quotas	60	(1)
The Disk Quotas Module	61	(1)
Enabling Quotas for a Filesystem	62	(1)
Disabling Quotas for a Filesystem	62	(1)
Setting Quotas for a User or Group	63	(1)
Copying Quotas to Multiple Users	63	(1)
Setting Grace Times	64	(1)
Setting Default Quotas for New Users	65	(1)
Other Operating Systems	66	(1)
Configuring the Disk Quotas Module	66	(1)
Module Access Control	66	(1)
Summary	67	(1)
8 Partitions, RAID, and LVM	68	(16)
Introduction to Hard Disk Partitions	68	(1)
The Partitions on Local Disks Module	69	(1)
Adding and Formatting a New Partition	70	(1)
Creating a New Filesystem	70	(1)
Partition Labels	71	(1)
Deleting or Changing a Partition	72	(1)
Module Access Control	73	(1)
Other Operating Systems	74	(1)
Introduction to RAID	74	(1)
The Linux RAID Module	75	(2)
Introduction to LVM	77	(1)
The Logical Volume Management Module	78	(1)
Creating a New Volume Group	79	(1)
Adding and Removing a Physical Volume	80	(1)
Creating and Deleting a Logical Volume	80	(1)
Resizing a Logical Volume	81	(1)
Creating a Snapshot	82	(1)
Summary	83	(1)
9 Bootup and Shutdown	84	(9)
Introduction to the Linux Boot Process	84	(1)
The Bootup and Shutdown Module	85	(1)
Configuring an Action to Start at Bootup	85	(1)
Starting and Stopping Actions	86	(1)
Adding a New Action	87	(2)
Rebooting or Shutting Down Your System	89	(1)
Configuring the Bootup and Shutdown Module	89	(1)
Other Operating Systems	89	(2)
The SysV mit Configuration Module	91	(1)
Summary	92	(1)
10 Scheduled Commands	93	(6)
Introduction to Cron Jobs	93	(1)
The Scheduled Cron Jobs Module	93	(1)
Creating a New Cron Job	94	(1)
Editing a Cron Job	95	(1)
Controlling Users' Access to Cron	96	(1)
Module Access Control Options	96	(1)
Configuring the Scheduled Cron Jobs Module	96	(1)
Other Operating Systems	97	(1)
The Scheduled Commands Module	97	(1)
Creating a New Scheduled Command	98	(1)
Summary	98	(1)
11 Process Management	99	(6)
Introduction to Processes	99	(1)
The Running Processes Module	99	(2)
Viewing, Killing, or Reprioritizing a Process	101	(1)
Searching for Processes	102	(1)
Running a Process	103	(1)
Module Access Control Options	103	(1)
Other Operating Systems	104	(1)
Summary	104	(1)
12 Software Packages	105	(8)
Introduction to Packages	105	(2)
The Software Packages Module	107	(1)
Installing a New Package	107	(2)
Finding and Removing a Package	109	(1)
Updating on Debian Linux	110	(1)
Updating on Red Hat Linux	111	(1)
Other Operating Systems	111	(1)
Summary	112	(1)
13 System Logs	113	(8)
Introduction to Logging	113	(2)
The System Logs Module	115	(1)
Adding a New Log File	115	(2)
Editing or Deleting a Log File	117	(1)
Module Access Control	118	(1)
Other Operating Systems	119	(1)
Summary	120	(1)
14 Filesystem Backups	121	(8)
Introduction to Backups with Dump	121	(1)
The Filesystem Backup Module	121	(1)
Adding a New Backup	122	(2)
Making a Backup	124	(1)
Editing or Deleting a Backup	125	(1)
Restoring a Backup	125	(1)
Configuring the Filesystem Backup Module	126	(2)
Other Operating Systems	128	(1)
Summary	128	(1)
15 Internet Services	129	(15)
Introduction to Internet Services	129	(1)
The Internet Services and Protocols Module	130	(3)
Enabling an Internet Service	133	(1)
Creating Your Own Internet Service	133	(2)
Creating and Editing RPC Programs	135	(1)
Configuring the Internet Services and Protocols Module	136	(2)
Other Operating Systems	138	(1)
The Extended Internet Services Module	139	(1)
Enabling or Editing an Extended Internet Service	140	(1)
Creating an Extended Internet Service	141	(1)
Editing Default Options	142	(1)
Summary	143	(1)
16 Network Configuration	144	(10)
Introduction to Linux Networking	144	(2)
Viewing and Editing Network Interfaces	146	(1)
Aching a Network Interface	147	(2)
Configuring Routing	149	(1)
Changing the Hostname or DNS Client Settings	150	(1)
Editing Host Addresses	151	(1)
Module Access Control	152	(1)
Other Operating Systems	153	(1)
Summary	153	(1)
17 Network Information Service	154	(11)
Introduction to NIS	154	(1)
Becoming an NIS Client	155	(2)
Setting Up an NIS Master Server	157	(2)
Editing NIS Tables	159	(1)
Securing Your NIS Server	160	(3)
Setting Up an NIS Slave Server	163	(1)
Configuring the NIS Client and Server Module	163	(1)
NIS on Solaris	163	(1)
Summary	164	(1)
18 PPP Server Configuration	165	(8)
Introduction to PPP on Linux	165	(1)
Configuring a PPP Server	166	(3)
Managing PPP Accounts	169	(2)
Restricting Access by Caller ID	171	(1)
Module Access Control	172	(1)
Summary	172	(1)
19 Firewall Configuration	173	(18)
Introduction to Firewalling with IPtables	173	(2)
The Linux Firewall Module	175	(2)
Allowing and Denying Network Traffic	177	(4)
Changing a Chain's Default Action	181	(1)
Editing Firewall Rules	182	(1)
Creating Your Own Chain	182	(1)
Setting Up Network Address Translation	183	(1)
Setting Up a Transparent Proxy	184	(1)
Setting Up Port Forwarding	185	(1)
Firewall Rule Conditions	186	(3)
Configuring the Linux Firewall Module	189	(1)
Summary	189	(2)
20 Setting the Date and Time	191	(4)
The System Time Module	191	(1)
Changing the System Time	192	(1)
Change the Hardware Time	192	(1)
Synchronizing Times with Another Server	193	(1)
Module Access Control	193	(1)
Other Operating Systems	193	(1)
Summary	194	(1)
21 Boot Loader Configuration	195	(10)
Introduction to Boot Loaders	195	(1)
The Linux Bootup Configuration Module	196	(1)
Booting a New Kernel with LILO	197	(1)
Booting Another Operating System with LILO	198	(1)
Editing Global LILO Options	199	(1)
The GRUB Boot Loader Module	200	(1)
Booting a New Linux Kernel or BSD with GRUB	201	(1)
Booting Another Operating System with GRUB	202	(1)
Editing Global GRUB Options	202	(1)
Installing GRUB	203	(1)
Configuring the GRUB Boot Loader Module	203	(1)
Summary	203	(2)
22 Printer Administration	205	(10)
Introduction to Printing on Linux	205	(1)
The Printer Administration Module	206	(1)
Adding a New Printer	206	(3)
Editing an Existing Printer	209	(1)
Managing Print Jobs	210	(1)
Configuring the Printer Administration Module	211	(1)
Module Access Control	212	(1)
Other Operating Systems	213	(1)
Summary	214	(1)
23 Voicemail Server Configuration	215	(5)
The Voicemail Server Module	215	(1)
Configuring Your System as an Answering Machine	216	(2)
Listening to Recorded Messages	218	(1)
Setting a Greeting Message	219	(1)
Summary	219	(1)
24 Remote Shell Login	220	(4)
The SSH/Telnet Login Module	220	(1)
Configuring the SSH/Telnet Login Module	220	(2)
The Command Shell Module	222	(1)
The Shell In A Box Module	223	(1)
Summary	223	(1)
25 Running Custom Commands	224	(8)
The Custom Commands Module	224	(1)
Creating a New Command	225	(2)
Parameter Types	227	(2)
Creating a New File Editor	229	(1)
Module Access Control	230	(1)
Configuring the Custom Commands Module	231	(1)
Summary	231	(1)
26 Webmin's File Manager	232	(12)
The File Manager Module	232	(1)
Navigating Directories and Viewing Files	232	(2)
Manipulating Files	234	(1)
Creating and Editing Files	234	(1)
Editing File Permissions	235	(1)
Creating Links and Directories	236	(1)
Finding Files	237	(1)
Editing EXT File Attributes	237	(1)
Editing XFS File Attributes	238	(1)
Editing File ACLS	239	(1)
Sharing Directories	240	(2)
Module Access Control	242	(1)
Summary	243	(1)
27 Perl Modules	244	(6)
Introduction to Peri Modules	244	(1)
Perl Modules in Webmin	245	(1)
Installing a Peri Module	245	(2)
Viewing and Removing a Peri Module	247	(1)
Configuring the Peri Modules Module	248	(1)
Summary	248	(2)
28 Status Monitoring with Webmin	250	(14)
The System and Server Status Module	250	(2)
Adding a New Monitor	252	(1)
Monitor Types	253	(7)
Setting Up Scheduled Monitoring	260	(2)
Module Access Control	262	(1)
Configuring the System and Server Status Module	262	(1)
Summary	263	(1)
29 Apache Web Server Configuration	264	(51)
Introduction to Apache	264	(1)
The Apache Webserver Module	265	(3)
Starting and Stopping Apache	268	(1)
Editing Pages on Your Web Server	268	(1)
Creating a New Virtual Host	269	(4)
Setting Per-Directory Options	273	(3)
Creating Aliases and Redirects	276	(3)
Running CGI Programs	279	(3)
Setting Up Server-Side Includes	282	(2)
Configuring Logging	284	(3)
Setting Up Custom Error Messages	287	(1)
Adding and Editing MIME Types	288	(1)
Password Protecting a Directory	289	(4)
Restricting Access by Client Address	293	(1)
Encodings, Character Sets, and Languages	294	(3)
Editing .htaccess Files	297	(2)
Setting Up User Web Directories	299	(2)
Configuring Apache as a Proxy Server	301	(3)
Setting Up SSL	304	(4)
Viewing and Editing Directives	308	(2)
Module Access Control	310	(1)
Configuring the Apache Webserver Module	311	(3)
Summary	314	(1)
30 DNS Server Configuration	315	(39)
Introduction to the Domain Name System	315	(3)
The BIND DNS Server Module	318	(3)
Creating a New Master Zone	321	(1)
Adding and Editing Records	322	(3)
Record Types	325	(5)
Editing a Master Zone	330	(2)
Creating a New Slave Zone	332	(2)
Editing a Slave Zone	334	(2)
Creating and Editing a Forward Zone	336	(1)
Creating a Root Zone	337	(1)
Editing Zone Defaults	338	(2)
Configuring Forwarding and Transfers	340	(1)
Editing Access Control Lists	341	(1)
Setting Up Partial Reverse Delegation	342	(2)
Using BIND Views	344	(2)
Module Access Control	346	(1)
Configuring the BIND DNS Server Module	347	(1)
The BIND 4 DNS Server Module	347	(6)
Summary	353	(1)
31 CVS Server Configuration	354	(7)
Introduction to CVS	354	(1)
The CVS Server Module	354	(1)
Setting Up the CVS Server	355	(1)
Using the CVS Server	356	(1)
Adding and Editing Users	356	(2)
Limiting User Access	358	(1)
Configuring the CVS Server	359	(1)
Browsing the Repository	359	(1)
Configuring the CVS Server Module	359	(1)
Summary	360	(1)
32 DHCP Server Configuration	361	(17)
Introduction to the Dynamic Host Configuration Protocol	361	(1)
The ISC DHCP Server	362	(1)
The DHCP Server Module	363	(2)
Adding and Editing Subnets	365	(4)
Viewing and Deleting Leases	369	(1)
Editing Global Client Options	370	(1)
Adding and Editing Fixed Hosts	370	(2)
Adding and Editing Shared Networks	372	(1)
Adding and Editing Groups	373	(1)
Module Access Control	374	(1)
Configuring the DHCP Server Module	375	(2)
Summary	377	(1)
33 Downloading Email with Fetchmail	378	(10)
Introduction to Fetchmail	378	(1)
The Fetchmail Mail Retrieval Module	379	(2)
Adding a New Mail Server to Check	381	(3)
Downloading Email	384	(1)
Running the Fetchmail Daemon	384	(1)
Editing Global Settings	385	(1)
Module Access Control	386	(1)
Configuring the Fetchmail Mail Retrieval Module	386	(1)
Summary	386	(2)
34 Managing Majordomo Mailing Lists	388	(17)
Introduction to Mailing Lists and Majordomo	388	(1)
The Majordomo List Manager Module	389	(2)
Using Other Mail Servers	391	(1)
Creating a Mailing List	391	(1)
Managing List Members	392	(1)
Editing List Information, Headers, and Footers	393	(2)
Editing Subscription Options	395	(1)
Editing Forwarded Email Options	396	(1)
Editing List Access Control	397	(1)
Moderating and Maintaining a Mailing List	398	(1)
Deleting a Mailing List	399	(1)
Creating a Digest List	399	(1)
Editing Digest Options	400	(1)
Editing Global Majordomo Options	401	(1)
Module Access Control	401	(1)
Configuring the Majordomo List Manager Module	402	(1)
Summary	402	(3)
35 The MySQL Database	405	(23)
Introduction to MySQL	405	(1)
The MySQL Database Server Module	406	(1)
Creating a New Database	407	(1)
Creating a New Table	408	(1)
Adding and Editing Fields	409	(3)
Field Types	412	(1)
Viewing and Editing Table Contents	412	(4)
Deleting Tables and Databases	416	(1)
Executing SQL Commands	417	(1)
Backing Up and Restoring a Database	417	(2)
Managing MySQL Users	419	(2)
Managing Database, Host, Table, and Field Permissions	421	(2)
Module Access Control	423	(1)
Configuring the MySQL Database Server Module	424	(3)
Summary	427	(1)
36 The PostgreSQL Database	428	(20)
Introduction to PostgreSQL	428	(1)
The PostgreSQL Database Server Module	429	(2)
Creating a New Database	431	(1)
Creating a New Table	431	(2)
Adding and Editing Fields	433	(1)
Deleting a Field	433	(1)
Field Types	434	(2)
Viewing and Editing Table Contents	436	(1)
Deleting Tables and Databases	436	(1)
Executing SQL Commands	437	(1)
Backing Up and Restoring a Database	437	(2)
Managing PostgreSQL Users	439	(2)
Managing PostgreSQL Groups	441	(1)
Restricting Client Access	441	(1)
Editing Object Privileges	442	(1)
Module Access Control	443	(1)
Configuring the PostgreSQL Database Server Module	444	(3)
Summary	447	(1)
37 Configuring Sendmail	448	(28)
Introduction to Internet Email	448	(1)
The Sendmail Configuration Module	449	(2)
Editing Local Domains and Domain Masquerading	451	(1)
Managing Email Aliases	452	(3)
Configuring Relaying	455	(1)
Managing Virtual Address Mappings	456	(1)
Configuring Domain Routing	457	(1)
Editing Global Sendmail Options	458	(2)
Viewing the Mail Queue	460	(1)
Reading Users' Email	461	(2)
Adding Sendmail Features with M4	463	(2)
Creating Autoreply Aliases	465	(1)
Creating Filter Aliases	466	(2)
Sendmail Module Access Control	468	(1)
Configuring the Sendmail Configuration Module	469	(6)
Summary	475	(1)
38 Configuring Qmail	476	(15)
Introduction to Qmail	476	(1)
The Qmail Configuration Module	477	(1)
Editing Local Domains	478	(1)
Managing Email Aliases	479	(1)
Configuring Relaying	480	(1)
Managing Virtual Mappings	481	(2)
Configuring Domain Routing	483	(1)
Editing Global Qmail Options	484	(1)
Editing Mail User Assignments	484	(2)
Viewing the Mail Queue	486	(1)
Reading Users' Email	486	(2)
Configuring the Qmail Configuration Module	488	(2)
Summary	490	(1)
39 Analyzing Log Files	491	(9)
The Webalizer Logfile Analysis Module	491	(1)
Editing Report Options	492	(4)
Generating and Viewing a Report	496	(1)
Reporting on Schedule	496	(1)
Adding Another Log File	497	(1)
Editing Global Options	498	(1)
Module Access Control	498	(1)
Summary	499	(1)
40 The ProFTPD Server	500	(25)
Introduction to FTP and ProFTPD	500	(1)
The ProFTPD Server Module	501	(2)
Running ProFTPD from inetd or xinetd	503	(1)
Using the ProFTPD Server Module	504	(1)
Creating Virtual Servers	505	(1)
Setting Up Anonymous FTP	506	(1)
Restricting Users to Their Home Directories	507	(1)
Limiting Who Can Log In	508	(2)
Setting Directory Listing Options	510	(1)
Message and Readme Files	511	(1)
Setting Per-Directory Options	512	(2)
Restricting Access to FTP Commands	514	(3)
Configuring Logging	517	(2)
Limiting Concurrent Logins	519	(1)
Restricting Clients by IP Address	520	(1)
Limiting Uploads	521	(2)
Manually Editing Directives	523	(1)
Configuring the ProFTPD Server Module	523	(1)
Summary	524	(1)
41 The WU-FTPD Server	525	(19)
Introduction to WU-FTPD	525	(1)
The WU-FTPD Server Module	526	(2)
Limiting Who Can Log In	528	(1)
Setting Up Anonymous FTP	529	(2)
Managing User Classes	531	(1)
Denying Access to Files	532	(2)
Setting Up Guest Users	534	(1)
Editing Directory Aliases	535	(1)
Message and Readme Files	536	(2)
Configuring Logging	538	(2)
Limiting Concurrent Logins	540	(1)
Restricting Clients by IP Address	541	(1)
Restricting Access to FTP Commands	541	(1)
Configuring the WU-FTPD Server Module	542	(1)
Summary	543	(1)
42 SSH Server Configuration	544	(10)
Introduction to SSH	544	(1)
The SSH Server Module	545	(1)
Restricting Access to the SSH Server	545	(2)
Network Configuration	547	(2)
Authentication Configuration	549	(2)
Editing Client Host Options	551	(1)
Setting Up SSH for New Users	552	(1)
Configuring the SSH Server Module	553	(1)
Summary	553	(1)
43 Windows File Sharing with Samba	554	(23)
Introduction to SMB and Samba	554	(2)
The Samba Windows File Sharing Module	556	(1)
Managing Samba Users	556	(3)
Adding a New File Share	559	(1)
Adding a New Printer Share	560	(2)
Viewing and Disconnecting Clients	562	(1)
Editing Share Security Options	563	(1)
Editing File Permission Settings	564	(1)
Editing File Naming Options	565	(1)
Editing Other File Share Options	566	(1)
Editing Printer Share Options	567	(1)
Editing Share Defaults	568	(1)
Configuring Networking	568	(3)
Configuring Authentication	571	(1)
Configuring Printers	572	(1)
Accessing SWAT from Webmin	573	(1)
Module Access Control	573	(1)
Configuring the Samba Windows File Sharing Module	574	(2)
Summary	576	(1)
44 Configuring the Squid Proxy Server	577	(28)
Introduction to Proxying and Squid	577	(1)
The Squid Proxy Server Module	578	(2)
Changing the Proxy Ports and Addresses	580	(1)
Adding Cache Directories	581	(2)
Editing Caching and Proxy Options	583	(1)
Introduction to Access Control Lists	584	(2)
Creating and Editing ACLS	586	(6)
Creating and Editing Proxy Restrictions	592	(1)
Setting Up Proxy Authentication	593	(2)
Configuring Logging	595	(1)
Connecting to Other Proxies	596	(2)
Clearing the Cache	598	(1)
Setting Up a Transparent Proxy	599	(1)
Viewing Cache Manager Statistics	599	(1)
Analyzing the Squid Logs	600	(1)
Module Access Control	601	(1)
Configuring the Squid Proxy Server Module	601	(3)
Summary	604	(1)
45 Filtering Email with Procmail	605	(10)
Introduction to Procmail	605	(1)
The Procmail Mail Filter Module	606	(1)
Setting Up Sendmail	606	(2)
Creating and Editing Actions	608	(3)
Creating and Editing Variable Assignments	611	(1)
Conditional Blocks and Include Files	612	(1)
Filtering Spam with SpamAssassin	613	(1)
Configuring the Procmail Mail Filter Module	614	(1)
Summary	614	(1)
46 Creating SSL Tunnels	615	(5)
Introduction to SSL and STunnel	615	(1)
The SSL Tunnels Module	616	(1)
Creating and Editing SSL Tunnels	617	(1)
Configuring the SSL Tunnels Module	618	(1)
Summary	619	(1)
47 Usermin Configuration	620	(23)
Introduction to Usermin	620	(1)
The Usermin Configuration Module	621	(1)
Starting and Stopping Usermin	621	(1)
Restricting Access to Usermin	622	(1)
Changing the Port and Address	623	(1)
Configuring the Usermin User Interface	623	(1)
Installing Usermin Modules	624	(1)
Changing the Default Language	625	(1)
Upgrading Usermin	625	(1)
Configuring Authentication	626	(2)
Editing Categories and Moving Modules	628	(1)
Changing and Installing Themes	629	(1)
Turning on SSL	630	(1)
Configuring Usermin Modules	631	(1)
Restricting Access to Modules	632	(4)
Limiting Who Can Log In	636	(2)
About the Usermin Modules	638	(3)
Configuring the Usermin Configuration Module	641	(1)
Summary	642	(1)
48 Cluster Software Management	643	(6)
Introduction to Webmin Clustering	643	(1)
The Cluster Software Packages Module	644	(1)
Registering a Server	645	(1)
Installing a Package	646	(1)
Searching for Packages	646	(1)
Deleting a Package	647	(1)
Exploring and Removing a Server	647	(1)
Refreshing the Package List	648	(1)
Configuring the Cluster Software Packages Module	648	(1)
Summary	648	(1)
49 Cluster User Management	649	(11)
The Cluster Users and Groups Module	649	(1)
Registering a Server	650	(1)
Creating a New User	651	(1)
Editing an Existing User	652	(1)
Deleting a User	653	(1)
reating a New Group	654	(1)
Editing an Existing Group	654	(2)
Deleting a Group	656	(1)
Refreshing User and Group Lists	656	(1)
Synchronizing Users and Groups	656	(2)
Listing and Removing a Server	658	(1)
Configuring the Cluster Users and Groups Module	659	(1)
Summary	659	(1)
50 Cluster Webmin Configuration	660	(9)
The Cluster Webmin Configuration Module	660	(1)
Registering a Server	661	(1)
Creating a New Webmin User	662	(1)
Editing or Deleting a Webmin User	662	(2)
Creating a New Webmin Group	664	(1)
Editing or Deleting a Webmin Group	664	(1)
Editing the User or Group ACL for a Module	665	(1)
Installing a Module or Theme	666	(1)
Viewing and Deleting a Module or Theme	667	(1)
Refreshing User and Module Lists	667	(1)
Listing and Removing a Server	668	(1)
Configuring the Cluster Webmin Configuration Module	668	(1)
Summary	668	(1)
51 Webmin Configuration	669	(19)
The Webmin Configuration Module	669	(1)
Restricting Access to Webmin	669	(1)
Changing the Port and Address	670	(1)
Setting Up Logging	671	(1)
Using Proxy Servers	672	(1)
Configuring the Webmin User Interface	672	(1)
Installing and Deleting Webmin Modules	673	(1)
Cloning a Webmin Module	674	(1)
Changing Your Operating System	675	(1)
Editing the Program Path and Environment Variables	676	(1)
Changing Webmin's Language	676	(1)
Editing Main Menu Settings	677	(1)
Upgrading Webmin	678	(1)
Installing Updates to Webmin	679	(2)
Configuring Authentication	681	(1)
Editing Categories and Moving Modules	682	(1)
Changing and Installing Themes	683	(1)
Referrer Checking	684	(1)
Allowing Unauthenticated Access to Modules	685	(1)
Turning on SSL	686	(1)
Setting Up a Certificate Authority	686	(1)
Summary	687	(1)
52 Webmin Access Control	688	(12)
Introduction to Webmin Users, Groups, and Permissions	688	(1)
The Webmin Users Module	689	(1)
Creating a New Webmin User	689	(2)
Editing a Webmin User	691	(1)
Editing Module Access Control	692	(2)
Creating and Editing Webmin Groups	694	(1)
Requesting a Client SSL Key	695	(2)
Viewing and Disconnecting Login Sessions	697	(1)
Module Access Control	697	(1)
Configuring the Webmin Users Module	698	(1)
Summary	699	(1)
53 Webmin Servers	700	(7)
The Webmin Servers Index Module	700	(1)
Adding a Webmin Server	701	(2)
Editing or Deleting a Webmin Server	703	(1)
Using Server Tunnels	703	(1)
Broadcasting and Scanning for Servers	704	(1)
How RPC Works	704	(1)
Module Access Control	705	(1)
Configuring the Webmin Servers Index Module	706	(1)
Summary	706	(1)
54 Logging in Webmin	707	(3)
Introduction to Logging	707	(1)
The Webmin Actions Log Module	708	(1)
Displaying Logs	708	(1)
Summary	709	(1)
55 Webmin Module Development	710	(11)
Introduction	710	(1)
Required Files	711	(1)
Module CGI Programs	712	(3)
Module Configuration	715	(2)
Look and Feel	717	(1)
Design Goals	718	(1)
Online Help	718	(1)
Module Packaging	719	(1)
Summary and Learning More	720	(1)
56 Advanced Module Development	721	(13)
Module Access Control	721	(2)
User Update Notification	723	(1)
Internationalization	723	(2)
File Locking	725	(1)
Action Logging	726	(2)
Pre- and Post-Install Scripts	728	(1)
Functions in Other Modules	728	(2)
Remote Procedure Calls	730	(2)
Creating Usermin Modules	732	(1)
Summary	733	(1)
57 Inside the Scheduled Cron Jobs Module	734	(7)
Module Design and CGI Programs	734	(1)
The cron-lib.pl Library Script	735	(2)
Module Configuration Settings	737	(1)
The lang Internationalization Directory	738	(1)
The acl_security.pl Access Control Script	738	(1)
The log_parser.pl Log Reporting Script	739	(1)
The useradmin_update.pl User
Synchronization Script	740	(1)
Summary	740	(1)
58 Creating Webmin Themes	741	(6)
Introduction to Themes	741	(2)
Overriding Images and Programs	743	(1)
Theme Functions	744	(2)
Summary	746	(1)
59 Inside the MSC Theme	747	(4)
Theme Design and Graphics	747	(1)
The index.cgi Program	748	(1)
The theme header Function	748	(1)
The theme footer Function	749	(1)
Summary	750	(1)
60 The Webmin API	751	(16)
API Functions	751	(14)
Summary	765	(2)
Index	767

Excerpts

This chapter explains what Webmin is, why it was written, and what you can expect from this book. What is Webmin? Webmin is a program that simplifies the process of managing a Linux or UNIX system. Traditionally, you have needed to manually edit configuration files and run commands to create accounts, set up web servers, or manage email forwarding. Webmin now lets you perform these tasks through an easy-to-use web interface, and automatically updates all of the required configuration files for you. This makes the job of administering your system much easier. Some of the things that you can do with Webmin include: Creating, editing, and deleting UNIX login accounts on your system Exporting files and directories to other systems with the NFS protocol Setting up disk quotas to control how much space users can take up with their files Installing, viewing, and removing software packages in RPM and other formats Changing your system's IP address, DNS settings, and routing configuration Setting up a firewall to protect your computer or give hosts on an internal LAN access to the Internet Creating and configuring virtual web sites for the Apache Web server Managing databases, tables, and fields in a MySQL or PostgreSQL database server Sharing files with Windows systems by configuring Samba These are just a few of the available functions. Webmin lets you configure almost all of the common services and popular servers on UNIX systems using a simple web interface. It protects you from the syntax errors and other mistakes that are often made when editing configuration files directly, and warns you before potentially dangerous actions. Because Webmin is accessed though a web browser, you can log in to it from any system that is connected to yours through a network. There is absolutely no difference between running it locally and running it remotely, and it is much easier to use over the network than other graphical configuration programs. Webmin has what is known as a modular design. This means that each of its functions is contained in a module that can generally be installed or removed independently from the rest of the program. Each module is responsible for managing some service or server, such as UNIX users, the Apache Web server, or software packages. If you have been manually configuring your system up till now, any existing settings will be recognized by Webmin. It always reads the standard configuration files on your system and updates them directly, instead of using its own separate database. This means that you can freely mix Webmin, manual configuration, and other programs or scripts that work in the same way. Even though this book is written for Linux users, Webmin can be used on many other flavors of UNIX as well, such as Solaris, FreeBSD, and HP/UX. One of its biggest strengths is its understanding of the differences between all these operating systems and the way it adjusts its user interface and behavior to fit your OS. This means that it can often hide the underlying differences between each UNIX variant and present a similar or identical interface no matter which one you are using. Webmin on its own is not particularly useful thoughit is only a configuration tool, so you must have programs installed for it to configure. For example, the Apache module requires that the actual Apache Web server be installed. Fortunately, all of the services and servers that Webmin manages are either included with most Linux distributions as standard, or can be freely downloaded and installed. Who Should Use Webmin? Webmin was written for use by people who have some Linux experience but are not familiar with the intricacies of system administration. Even though it makes the process of creating UNIX users or managing the Squid proxy server easy, you must first have some ide