TWiki External Links

URLs starting with file, ftp, gopher, http, https, irc, mailto, news, nntp and telnet are linked automatically if preceded by whitespace or parenthesis. External links are indicated with a trailing External link icon, and open up in a new browser tab or window; the behavior of both can be set in configure or preferences variables. Links can be prevented with an ! exclamation point prefix.

Note: if a link is written directly as HTML (<a href="http://...">...</a>), it is not subject to the external link conversion.

Preferences Variables

Users can customize the behavior of the external links (typically in the WebPreferences page).

Variable Value Description
EXTERNALLINKSINNEWWINDOW on/off Open external links in a new browser tab or window
EXTERNALLINKSICON on/off Show a trailing External link icon
INTERNALLINKDOMAINS (see below) Add domain names that should not be regarded as "external"

The value of INTERNALLINKDOMAINS is expected to be a comma-separated list of domain names.

Each domain name entry should be any of the below:

  • A proper domain name (such as - not including any of the subdomains
  • A domain name with a preceding dot (such as - indicating any subdomains (e.g. but not including the domain itself (
  • A single dot (.) - indicating any "one-word" domain names, typically used in an intranet.
  • A topic name in the format topic:TopicName or topic:WebName.TopicName. The WebName defaults to the base web (%BASEWEB%) in the current context.

If a topic name is specified, the topic is expected to contain a table, where the left-most column is for the domains.

| *Domain* |
| |
| |
| |


Administrators can configure the default settings of the external link behaviors. (configure)

ConfigSorted ascending Default Description
$cfg{Links}{ExternalLinksIcon} on Show a trailing External link icon
$cfg{Links}{ExternalLinksInNewWindow} on Open external links in a new browser tab or window
$cfg{Links}{InternalLinkDomains} (unset) Add domain names that should not be regarded as "external"

See above for the value of InternalLinkDomains. The WebName in the topic:TopicName defaults to the system web (%SYSTEMWEB%, or "TWiki").

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