Bug 208279

Summary:	hosts man page inaccurately states "For each host a single line should be present" while there can be 2 lines, IPv4 and IPv6
Product:	Documentation	Reporter:	Jernej Jakob (jernej.jakob)
Component:	man-pages	Assignee:	documentation_man-pages (documentation_man-pages)
Status:	RESOLVED CODE_FIX
Severity:	normal	CC:	mtk.manpages
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:		Subsystem:
Regression:	No	Bisected commit-id:

Description Jernej Jakob 2020-06-22 10:55:27 UTC

A single hostname can have 2 lines, one for IPv4 and one for IPv6. The man page should be updated to reflect that.

Comment 1 Michael Kerrisk 2020-06-30 07:48:03 UTC

I think this report has been addressed by the following patch from Thomas Bartelsmeier, so I'm closing this.

diff --git a/man5/hosts.5 b/man5/hosts.5
index cb055f5f6..1230f9303 100644
--- a/man5/hosts.5
+++ b/man5/hosts.5
@@ -42,6 +42,7 @@ line should be present with the following information:
 IP_address canonical_hostname [aliases...]
 .RE
 .PP
+The IP address can conform to either IPv4 or IPv6.
 Fields of the entry are separated by any number of blanks and/or
 tab characters.
 Text from a "#" character until the end of the line is
@@ -53,6 +54,8 @@ alphabetic character and end with an alphanumeric character.
 Optional aliases provide for name changes, alternate spellings,
 shorter hostnames, or generic hostnames (for example,
 .IR localhost ).
+If required, a host may have two separate entries in this file;
+one for each version of the Internet Protocol (IPv4 and IPv6).
 .PP
 The Berkeley Internet Name Domain (BIND) Server implements the
 Internet name server for UNIX systems.