The Trac Configuration File

Global Configuration

In versions prior to 0.11, the global configuration was by default located in $prefix/share/trac/conf/trac.ini or sometimes /etc/trac/trac.ini depending on the distribution. If you're upgrading, you may want to specify that file to inherit from.

Global options will be merged with the environment-specific options, where local options override global options. The options file is specified as follows:

[inherit]
file = /usr/share/trac/conf/trac.ini

Note that you can also specify a global option file when creating a new project, by adding the option --inherit=/path/to/global/options to trac-admin's initenv command. If you would not do this but nevertheless intend to use a global option file with your new environment, you would have to go through the newly generated conf/trac.ini file and delete the entries that would otherwise override those set in the global file.

Reference

This is a brief reference of available configuration options.

[account-manager]

account_changes_notify_addresses	List of email addresses that get notified of user changes, ie, new user, password change and delete user.
authentication_url
force_passwd_change	Forge the user to change password when it's reset.
generated_password_length	Length of the randomly-generated passwords created when resetting the password for an account.
hash_method
htdigest_realm
notify_actions	Comma separated list of actions to notify of. Available actions 'new', 'change', 'delete'.
password_file	Path to the users file. Leave blank to locate the users file by reading svnserve.conf
password_format
password_store

[attachment]

max_size	Maximum allowed file size (in bytes) for ticket and wiki attachments.
render_unsafe_content	Whether attachments should be rendered in the browser, or only made downloadable. Pretty much any file may be interpreted as HTML by the browser, which allows a malicious user to attach a file containing cross-site scripting attacks. For public sites where anonymous users can create attachments it is recommended to leave this option disabled (which is the default).

[browser]

color_scale	Enable colorization of the age column. This uses the same color scale as the source code annotation: blue is older, red is newer. (since 0.11)
downloadable_paths	List of repository paths that can be downloaded. Leave the option empty if you want to disable all downloads, otherwise set it to a comma-separated list of authorized paths (those paths are glob patterns, i.e. "*" can be used as a wild card) (since 0.10)
hide_properties	Comma-separated list of version control properties to hide from the repository browser. (since 0.9)
intermediate_color	(r,g,b) color triple to use for the color corresponding to the intermediate color, if two linear interpolations are used for the color scale (see intermediate_point). If not set, the intermediate color between oldest_color and newest_color will be used. (since 0.11)
intermediate_point	If set to a value between 0 and 1 (exclusive), this will be the point chosen to set the intermediate_color for interpolating the color value. (since 0.11)
newest_color	(r,g,b) color triple to use for the color corresponding to the newest color, for the color scale used in blame or the browser age column if color_scale is enabled. (since 0.11)
oldest_color	(r,g,b) color triple to use for the color corresponding to the oldest color, for the color scale used in blame or the browser age column if color_scale is enabled. (since 0.11)
oneliner_properties	Comma-separated list of version control properties to render as oneliner wiki content in the repository browser. (since 0.11)
render_unsafe_content	Whether raw files should be rendered in the browser, or only made downloadable. Pretty much any file may be interpreted as HTML by the browser, which allows a malicious user to create a file containing cross-site scripting attacks. For open repositories where anyone can check-in a file, it is recommended to leave this option disabled (which is the default).
wiki_properties	Comma-separated list of version control properties to render as wiki content in the repository browser. (since 0.11)

[changeset]

max_diff_bytes	Maximum total size in bytes of the modified files (their old size plus their new size) for which the changeset view will attempt to show the diffs inlined (since 0.10).
max_diff_files	Maximum number of modified files for which the changeset view will attempt to show the diffs inlined (since 0.10).
wiki_format_messages	Whether wiki formatting should be applied to changeset messages. If this option is disabled, changeset messages will be rendered as pre-formatted text.

[fullblog]

default_postname	Option for a default naming scheme for new posts. The string can include substitution markers for time (UTC) and user: %Y=year, %m=month, %d=day, %H=hour, %M=minute, %S=second, $USER. Example template string: %Y/%m/%d/my_topic
month_names	Ability to specify a list of month names for display in groupings. If empty it will make a list from default locale setting. Enter list of 12 months like: month_names = January, February, ..., December
num_items_front	Option to specify how many recent posts to display on the front page of the Blog (and RSS feeds).
personal_blog	When using the Blog as a personal blog (only one author), setting to 'True' will disable the display of 'Browse by author:' in sidebar, and also removes various author links and references.

[git]

cached_repository	wrap GitRepository in CachedRepository
git_bin	path to git executable (relative to trac project folder!)
persistent_cache	enable persistent caching of commit tree
shortrev_len	length rev sha sums should be tried to be abbreviated to (must be >= 4 and <= 40)

[header_logo]

alt	Alternative text for the header logo.
height	Height of the header logo image in pixels.
link	URL to link to from header logo.
src	URL of the image to use as header logo.
width	Width of the header logo image in pixels.

[inherit]

plugins_dir	Path of the directory containing additional plugins. Plugins in that directory are loaded in addition to those in the directory of the environment plugins, with this one taking precedence. (since 0.11)
templates_dir	Path to the shared templates directory. Templates in that directory are loaded in addition to those in the environments templates directory, but the latter take precedence. (since 0.11)

[iniadmin]

excludes	Excludes this options. Comma separated list as section:name.
passwords	Show input-type as password instead of text. Comma separated list as section:name.

[irclogs]

action_regex	Default match for ACTION lines. ex. 2009-05-20T10:10:10 * nick hits someone with a fish ex. 2009-05-20 10:10:10 | * nick hits someone with a fish Can be overridden by format.
basepath	Default basepath for logs. Can be overridden by format.
channel	Default channel. Can be overriden by channel
charset	Channel charset
comment_regex	Default match for COMMENT lines. ex. 2009-05-20T10:10:10 <nick> how's it going? ex. 2009-05-20 10:10:10 | <nick> how's it going? Can be overridden by format.
format	The name of the default format to use.
format.bip.action_regex
format.bip.comment_regex
format.bip.join_regex
format.bip.kick_regex
format.bip.mode_regex
format.bip.nick_regex
format.bip.notice_regex
format.bip.part_regex
format.bip.paths
format.bip.quit_regex
format.bip.timestamp_format
format.bip.timestamp_regex
format.bip.topic_regex
format.gozer.paths
format.gozer.timestamp_format
hidden_users	A list of users that should be hidden by default
join_regex	Default match on JOIN lines. ex. 2009-05-20T10:10:10 *** nick has joined #channel ex. 2009-05-20 10:10:10 | nick has joined Can be overridden by format.
kick_regex	Default match KICK lines. ex. 2009-05-20T10:10:10 *** kickedguy was kicked by nick ex. 2009-05-20 10:10:10 | kickedguy was kicked by nick Can be overridden by format.
match_order	Default order that lines are checked against. This matters if a line could match multiple regexes. Can be overridden by format.
mode_regex	Default match on MODE lines. ex. 2009-05-20T10:10:10 *** nick sets mode: +v guy ex. 2009-05-20 10:10:10 | nick sets mode: +v guy Can be overridden by format.
network	Default network. Can be overriden by channel
nick_regex	Default match on NICK lines. ex. 2009-05-20T10:10:10 *** nick is now known as nick2 ex. 2009-05-20 10:10:10 | nick is now known as nick2" Can be overridden by format.
notice_regex	Default match on NOTICE lines. ex. 2009-05-20T10:10:10 -nick- hello everyone! ex. 2009-05-20 10:10:10 | -nick- hello everyone!" Can be overridden by format.
part_regex	Default match on PART lines. ex. 2009-05-20T10:10:10 *** nick has left #channel ex. 2009-05-20 10:10:10 | nick has left Can be overridden by format.
paths	Default format for complete path to log files. Include parameters: %Y, %m, %d, etc. : all strftime formatting supported %(network)s : network %(channel)s : channel Example: %(channel)s/%(channel)s.%Y-%m-%d.log %(channel)s.%Y%m%d.log Can be overridden by format.
quit_regex	Default match QUIT lines. ex. 2009-05-20T10:10:10 *** nick has quit IRC ex. 2009-05-20 10:10:10 | nick has quit: I'm outta he--ya Can be overridden by format.
show_msg_types	There are message types to show by default
timestamp_format	Default format to use when parsing timestamp to datetime. Can be overridden by format.
timestamp_regex	Default partial regex used at the beginning of all other regexes. It is only used if explicitly included in the other regexes as %(timestamp_regex)s ex. 2009-05-20T10:10:10 ex. 2009-05-20 10:10:10 Can be overriedden by format.
timezone	Default timezone that irc is logged in. This is needed so we can convert the incoming date to the date in the irc log. This can be overridden by the file format.
topic_regex	Default match on TOPIC lines. ex. 2009-05-20T10:10:10 *** nick changes topic to "new topic" ex. 2009-05-20 10:10:10 | nick changes topic to "new topic" Can be overridden by format.

[logging]

log_file	If log_type is file, this should be a path to the log-file.
log_format	Custom logging format. If nothing is set, the following will be used: Trac[$(module)s] $(levelname)s: $(message)s In addition to regular key names supported by the Python logger library library (see  http://docs.python.org/lib/node422.html), one could use: - $(path)s the path for the current environment - $(basename)s the last path component of the current environment - $(project)s the project name Note the usage of $(...)s instead of %(...)s as the latter form would be interpreted by the ConfigParser? itself. Example: ($(thread)d) Trac[$(basename)s:$(module)s] $(levelname)s: $(message)s (since 0.10.5)
log_level	Level of verbosity in log. Should be one of (CRITICAL, ERROR, WARN, INFO, DEBUG).
log_type	Logging facility to use. Should be one of (none, file, stderr, syslog, winlog).

[milestone]

stats_provider

Name of the component implementing ITicketGroupStatsProvider, which is used to collect statistics on groups of tickets for display in the milestone views.

[mimeviewer]

max_preview_size	Maximum file size for HTML preview. (since 0.9)
mime_map	List of additional MIME types and keyword mappings. Mappings are comma-separated, and for each MIME type, there's a colon (":") separated list of associated keywords or file extensions. (since 0.10)
pygments_default_style	The default style to use for Pygments syntax highlighting.
pygments_modes	List of additional MIME types known by Pygments. For each, a tuple mimetype:mode:quality has to be specified, where mimetype is the MIME type, mode is the corresponding Pygments mode to be used for the conversion and quality is the quality ratio associated to this conversion. That can also be used to override the default quality ratio used by the Pygments render.
silvercity_modes	List of additional MIME types known by SilverCity?. For each, a tuple mimetype:mode:quality has to be specified, where mimetype is the MIME type, mode is the corresponding SilverCity? mode to be used for the conversion and quality is the quality ratio associated to this conversion. That can also be used to override the default quality ratio used by the SilverCity? render, which is 3 (since 0.10).
tab_width	Displayed tab width in file preview. (since 0.9)
treat_as_binary	Comma-separated list of MIME types that should be treated as binary data. (since 0.11.5)

[notification]

admit_domains	Comma-separated list of domains that should be considered as valid for email addresses (such as localdomain).
always_notify_owner	Always send notifications to the ticket owner (since 0.9).
always_notify_reporter	Always send notifications to any address in the reporter field.
always_notify_updater	Always send notifications to the person who causes the ticket property change and to any previous updater of that ticket.
email_sender	Name of the component implementing IEmailSender. This component is used by the notification system to send emails. Trac currently provides SmtpEmailSender for connecting to an SMTP server, and SendmailEmailSender for running a sendmail-compatible executable. (since 0.12)
ignore_domains	Comma-separated list of domains that should not be considered part of email addresses (for usernames with Kerberos domains).
mime_encoding	Specifies the MIME encoding scheme for emails. Valid options are 'base64' for Base64 encoding, 'qp' for Quoted-Printable, and 'none' for no encoding, in which case mails will be sent as 7bit if the content is all ASCII, or 8bit otherwise. (since 0.10)
sendmail_path	Path to the sendmail executable. The sendmail program must accept the -i and -f options. (since 0.12)
smtp_always_bcc	Email address(es) to always send notifications to, addresses do not appear publicly (Bcc:). (since 0.10).
smtp_always_cc	Email address(es) to always send notifications to, addresses can be seen by all recipients (Cc:).
smtp_default_domain	Default host/domain to append to address that do not specify one.
smtp_enabled	Enable email notification.
smtp_from	Sender address to use in notification emails.
smtp_from_name	Sender name to use in notification emails.
smtp_password	Password for SMTP server. (since 0.9)
smtp_port	SMTP server port to use for email notification.
smtp_replyto	Reply-To address to use in notification emails.
smtp_server	SMTP server hostname to use for email notifications.
smtp_subject_prefix	Text to prepend to subject line of notification emails. If the setting is not defined, then the [$project_name] prefix. If no prefix is desired, then specifying an empty option will disable it. (since 0.10.1).
smtp_user	Username for SMTP server. (since 0.9)
ticket_subject_template	A Genshi text template snippet used to get the notification subject. By default, the subject template is $prefix #$ticket.id: $summary. $prefix being the value of the smtp_subject_prefix option. (since 0.11)
use_public_cc	Recipients can see email addresses of other CC'ed recipients. If this option is disabled (the default), recipients are put on BCC. (since 0.10)
use_short_addr	Permit email address without a host/domain (i.e. username only). The SMTP server should accept those addresses, and either append a FQDN or use local delivery. (since 0.10)
use_tls	Use SSL/TLS to send notifications over SMTP. (since 0.10)

[project]

admin	E-Mail address of the project's administrator.
admin_trac_url	Base URL of a Trac instance where errors in this Trac should be reported. This can be an absolute or relative URL, or '.' to reference this Trac instance. An empty value will disable the reporting buttons. (since 0.11.3)
descr	Short description of the project.
footer	Page footer text (right-aligned).
icon	URL of the icon of the project.
name	Name of the project.
url	URL of the main project web site, usually the website in which the base_url resides.

[query]

default_anonymous_query	The default query for anonymous users. The query is either in query language syntax, or a URL query string starting with ? as used in query: Trac links. (since 0.11.2)
default_query	The default query for authenticated users. The query is either in query language syntax, or a URL query string starting with ? as used in query: Trac links. (since 0.11.2)
items_per_page	Number of tickets displayed per page in ticket queries, by default (since 0.11)
ticketlink_query	The base query to be used when linkifying values of ticket fields. The query is a URL query string starting with ? as used in query: Trac links. (since 0.12)

[report]

items_per_page	Number of tickets displayed per page in ticket reports, by default (since 0.11)
items_per_page_rss	Number of tickets displayed in the rss feeds for reports (since 0.11)

[revisionlog]

default_log_limit

Default value for the limit argument in the TracRevisionLog (since 0.11).

[roadmap]

stats_provider

Name of the component implementing ITicketGroupStatsProvider, which is used to collect statistics on groups of tickets for display in the roadmap views.

[search]

default_disabled_filters	Specifies which search filters should be disabled by default on the search page. This will also restrict the filters for the quick search function. Search filters can still be manually enabled by the user on the search page. (since 0.12)
min_query_length	Minimum length of query string allowed when performing a search.

[sqlite]

extensions

Paths to sqlite extensions, relative to Trac environment's directory or absolute. (since 0.12)

[svn]

branches	Comma separated list of paths categorized as branches. If a path ends with '*', then all the directory entries found below that path will be included. Example: /trunk, /branches/*, /projectAlpha/trunk, /sandbox/*
tags	Comma separated list of paths categorized as tags. If a path ends with '*', then all the directory entries found below that path will be included. Example: /tags/*, /projectAlpha/tags/A-1.0, /projectAlpha/tags/A-v1.1

[tags]

ignore_closed_tickets	Do not collect tags from closed tickets.
ticket_fields	List of ticket fields to expose as tags.

[ticket]

default_cc	Default cc: list for newly created tickets.
default_component	Default component for newly created tickets.
default_description	Default description for newly created tickets.
default_keywords	Default keywords for newly created tickets.
default_milestone	Default milestone for newly created tickets.
default_owner	Default owner for newly created tickets.
default_priority	Default priority for newly created tickets.
default_resolution	Default resolution for resolving (closing) tickets (since 0.11).
default_severity	Default severity for newly created tickets.
default_summary	Default summary (title) for newly created tickets.
default_type	Default type for newly created tickets (since 0.9).
default_version	Default version for newly created tickets.
max_comment_size	Don't accept tickets with a too big comment. (since 0.11.2)
max_description_size	Don't accept tickets with a too big description. (since 0.11).
preserve_newlines	Whether Wiki formatter should respect the new lines present in the Wiki text. If set to 'default', this is equivalent to 'yes' for new environments but keeps the old behavior for upgraded environments (i.e. 'no'). (since 0.11).
restrict_owner	Make the owner field of tickets use a drop-down menu. Be sure to understand the performance implications before activating this option. See Assign-to as Drop-Down List (since 0.9).
workflow	Ordered list of workflow controllers to use for ticket actions (since 0.11).

[timeline]

abbreviated_messages	Whether wiki-formatted event messages should be truncated or not. This only affects the default rendering, and can be overriden by specific event providers, see their own documentation. (Since 0.11)
changeset_collapse_events	Whether consecutive changesets from the same author having exactly the same message should be presented as one event. That event will link to the range of changesets in the log view. (since 0.11)
changeset_long_messages	Whether wiki-formatted changeset messages should be multiline or not. If this option is not specified or is false and wiki_format_messages is set to true, changeset messages will be single line only, losing some formatting (bullet points, etc).
changeset_show_files	Number of files to show (-1 for unlimited, 0 to disable). This can also be location, for showing the common prefix for the changed files. (since 0.11).
default_daysback	Default number of days displayed in the Timeline, in days. (since 0.9.)
max_daysback	Maximum number of days (-1 for unlimited) displayable in the Timeline. (since 0.11)
newticket_formatter	Which formatter flavor (e.g. 'html' or 'oneliner') should be used when presenting the description for new tickets. If 'oneliner', the [timeline] abbreviated_messages option applies. (since 0.11).
ticket_show_details	Enable the display of all ticket changes in the timeline, not only open / close operations (since 0.9).

[trac]

authz_file	The path to the Subversion  authorization (authz) file. To enable authz permission checking, the AuthzSourcePolicy permission policy must be added to [trac] permission_policies.
authz_module_name	The module prefix used in the authz_file for the default repository. If left empty, the global sections will be used.
auto_preview_timeout	Inactivity timeout in seconds after which the automatic wiki preview triggers an update. Set this to 0 to disable automatic preview. (since 0.12)
auto_reload	Automatically reload template files after modification.
backup_dir	Database backup location
base_url	Reference URL for the Trac deployment. This is the base URL that will be used when producing documents that will be used outside of the web browsing context, like for example when inserting URLs pointing to Trac resources in notification e-mails.
database	Database connection string for this project
debug_sql	Show the SQL queries in the Trac log, at DEBUG level. (Since 0.11.5)
default_charset	Charset to be used when in doubt.
default_handler	Name of the component that handles requests to the base URL. Options include TimelineModule, RoadmapModule, BrowserModule, QueryModule, ReportModule, TicketModule and WikiModule. The default is WikiModule. (since 0.9)
default_timezone	The default timezone to use
genshi_cache_size	The maximum number of templates that the template loader will cache in memory. The default value is 128. You may want to choose a higher value if your site uses a larger number of templates, and you have enough memory to spare, or you can reduce it if you are short on memory.
htdocs_location	Base URL of the core static resources.
mainnav	Order of the items to display in the mainnav navigation bar, listed by IDs. See also TracNavigation.
metanav	Order of the items to display in the metanav navigation bar, listed by IDs. See also TracNavigation.
mysqldump_path	Location of mysqldump for MySQL database backups
never_obfuscate_mailto	Never obfuscate mailto: links explicitly written in the wiki, even if show_email_addresses is false or the user has not the EMAIL_VIEW permission (since 0.11.6).
permission_policies	List of components implementing IPermissionPolicy, in the order in which they will be applied. These components manage fine-grained access control to Trac resources. Defaults to the DefaultPermissionPolicy? (pre-0.11 behavior) and LegacyAttachmentPolicy? (map ATTACHMENT_* permissions to realm specific ones)
permission_store	Name of the component implementing IPermissionStore, which is used for managing user and group permissions.
pg_dump_path	Location of pg_dump for Postgres database backups
repository_dir	Path to the default repository. This can also be a relative path (since 0.11). This option is deprecated, and repositories should be defined in the [repositories] section, or using the "Repositories" admin panel. (since 0.12)
repository_sync_per_request	List of repositories that should be synchronized on every page request. Leave this option empty if you have set up post-commit hooks calling trac-admin $ENV changeset added on all your repositories (recommended). Otherwise, set it to a comma-separated list of repository names. Note that this will negatively affect performance, and will prevent changeset listeners from receiving events from the repositories specified here. The default is to synchronize the default repository, for backward compatibility. (since 0.12)
repository_type	Default repository connector type. (since 0.10) This is also used as the default repository type for repositories defined in [repositories] or using the "Repositories" admin panel. (since 0.12)
request_filters	Ordered list of filters to apply to all requests (since 0.10).
resizable_textareas	Make <textarea> fields resizable. Requires JavaScript. (since 0.12)
secure_cookies	Restrict cookies to HTTPS connections. When true, set the secure flag on all cookies so that they are only sent to the server on HTTPS connections. Use this if your Trac instance is only accessible through HTTPS. (since 0.11.2)
show_email_addresses	Show email addresses instead of usernames. If false, we obfuscate email addresses. (since 0.11)
show_ip_addresses	Show IP addresses for resource edits (e.g. wiki). (since 0.11.3)
timeout	Timeout value for database connection, in seconds. Use '0' to specify no timeout. (Since 0.11)
use_base_url_for_redirect	Optionally use [trac] base_url for redirects. In some configurations, usually involving running Trac behind a HTTP proxy, Trac can't automatically reconstruct the URL that is used to access it. You may need to use this option to force Trac to use the base_url setting also for redirects. This introduces the obvious limitation that this environment will only be usable when accessible from that URL, as redirects are frequently used. (since 0.10.5)

[wiki]

ignore_missing_pages	Enable/disable highlighting CamelCase links to missing pages (since 0.9).
max_size	Maximum allowed wiki page size in bytes. (since 0.11.2)
render_unsafe_content	Enable/disable the use of unsafe HTML tags such as <script> or <embed> with the HTML WikiProcessor (since 0.10.4). For public sites where anonymous users can edit the wiki it is recommended to leave this option disabled (which is the default).
split_page_names	Enable/disable splitting the WikiPageNames with space characters (since 0.10).

[zeep]

apikey

Zeep Mobile API Key

[components]

This section is used to enable or disable components provided by plugins, as well as by Trac itself. The component to enable/disable is specified via the name of the option. Whether its enabled is determined by the option value; setting the value to enabled or on will enable the component, any other value (typically disabled or off) will disable the component.

The option name is either the fully qualified name of the components or the module/package prefix of the component. The former enables/disables a specific component, while the latter enables/disables any component in the specified package/module.

Consider the following configuration snippet:

[components]
trac.ticket.report.ReportModule = disabled
webadmin.* = enabled

The first option tells Trac to disable the report module. The second option instructs Trac to enable all components in the webadmin package. Note that the trailing wildcard is required for module/package matching.

See the Plugins page on About Trac to get the list of active components (requires CONFIG_VIEW permissions.)

See also: TracPlugins

[ticket-custom]

In this section, you can define additional fields for tickets. See TracTicketsCustomFields for more details.

[ticket-workflow]

(since 0.11)

The workflow for tickets is controlled by plugins. By default, there's only a ConfigurableTicketWorkflow component in charge. That component allows the workflow to be configured via this section in the trac.ini file. See TracWorkflow for more details.

[milestone-groups]

(since 0.11)

As the workflow for tickets is now configurable, there can be many ticket states, and simply displaying closed tickets vs. all the others is maybe not appropriate in all cases. This section enables one to easily create groups of states that will be shown in different colors in the milestone progress bar.

Example configuration (which is also the default):

closed = closed
closed.order = 0                     # sequence number in the progress bar
closed.query_args = group=resolution # optional extra param for the query
closed.overall_completion = true     # count for overall completion

active = *                           # one catch-all group is allowed
active.order = 1
active.css_class = open              # CSS class for this interval
active.label = in progress           # Displayed label for this group

The definition consists in a comma-separated list of accepted status. Also, '*' means any status and could be used to associate all remaining states to one catch-all group.

The CSS class can be one of: new (yellow), open (no color) or closed (green). New styles can easily be added using the following selector: table.progress td.<class>

[svn:externals]

(since 0.11)

The TracBrowser for Subversion can interpret the svn:externals property of folders out of the box. However, if those externals are not using the http: protocol, or if a link to a different repository browser (such another Trac or  ViewVC) is desired, then Trac needs to be able to map an external prefix to this other URL.

This mapping is done in the [svn:externals] section of the TracIni

Example:

[svn:externals]
1 = svn://server/repos1 http://trac/proj1/browser/$path?rev=$rev
2 = svn://server/repos2 http://trac/proj2/browser/$path?rev=$rev
3 = http://theirserver.org/svn/eng-soft       http://ourserver/viewvc/svn/$path/?pathrev=25914
4 = svn://anotherserver.com/tools_repository  http://ourserver/trac/support/browser/$path?rev=$rev

With the above, the svn://anotherserver.com/tools_repository/tags/1.1/tools external will be mapped to http://ourserver/trac/support/browser/tags/1.1/tools?rev= (and rev will be set to the appropriate revision number if the external additionally specifies a revision, see the  SVN Book on externals for more details).

Note that the number used as a key in the above section is purely used as a place holder, as the URLs themselves can't be used as a key due to various limitations in the configuration file parser.

---

See also: TracGuide, TracAdmin, TracEnvironment