X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=man%2Fnss-myhostname.xml;h=cf2b0200f2e16ede7604afbc0d13765fbf043f4a;hb=dab2bce81ed3e97d059d56e66f560aa25d9c2d63;hp=bd3f635692246903ed6b293dc4bf2ff47a5c550c;hpb=16eb4da97e1bfe7f9416a0622b1a06408e550423;p=elogind.git diff --git a/man/nss-myhostname.xml b/man/nss-myhostname.xml index bd3f63569..cf2b0200f 100644 --- a/man/nss-myhostname.xml +++ b/man/nss-myhostname.xml @@ -1,6 +1,6 @@ + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> - - - - nss-myhostname - systemd - - - - Developer - Lennart - Poettering - lennart@poettering.net - - - - - - nss-myhostname - 8 - - - - nss-myhostname - Provide host name resolution for the locally - configured system hostname. - - - - - nss-myhostname.la - - - - - Description - - nss-myhostname is a plugin for the GNU Name Service Switch - (NSS) functionality of the GNU C Library (glibc) - providing host name resolution for the locally configured system - hostname as returned by - gethostname2. - Various software relies on an always resolvable local host name. When - using dynamic hostnames this is usually achieved by patching - /etc/hosts at the same time as changing the host - name. This however is not ideal since it requires a writable - /etc file system and is fragile because the file - might be edited by the administrator at the same time. nss-myhostname - simply returns all locally configure public IP addresses, or -- if none - are configured -- the IPv4 address 127.0.0.2 (wich is on the local - loopback) and the IPv6 address ::1 (which is the local host) for - whatever system hostname is configured locally. Patching - /etc/hosts is thus no longer necessary. - - To activate the NSS modules, - has to be added to the line starting with "hosts:" in - /etc/nsswitch.conf - - It is recommended to put - last in the nsswitch.conf line to make - sure that this mapping is only used as fallback, and any DNS - or /etc/hosts based mapping takes precedence. - - - - Example - - -# /etc/nsswitch.conf - -passwd: compat -group: compat -shadow: compat - -hosts: files dns myhostname + + + + nss-myhostname + systemd + + + + Developer + Lennart + Poettering + lennart@poettering.net + + + + + + nss-myhostname + 8 + + + + nss-myhostname + libnss_myhostname.so.2 + Provide hostname resolution for the locally + configured system hostname. + + + + libnss_myhostname.so.2 + + + + Description + + nss-myhostname is a plugin for the GNU + Name Service Switch (NSS) functionality of the GNU C Library + (glibc) primarily providing hostname resolution + for the locally configured system hostname as returned by + gethostname2. + The precise hostnames resolved by this module are: + + + The local, configured hostname is resolved to + all locally configured IP addresses ordered by their scope, or + — if none are configured — the IPv4 address 127.0.0.2 (which + is on the local loopback) and the IPv6 address ::1 (which is the + local host). + + The hostname localhost is + resolved to the IP addresses 127.0.0.1 and + ::1. + + The hostname gateway is + resolved to all current default routing gateway addresses, + ordered by their metric. This assigns a stable hostname to the + current gateway, useful for referencing it independently of the + current network configuration state. + + + + Various software relies on an always-resolvable local + hostname. When using dynamic hostnames, this is traditionally + achieved by patching /etc/hosts at the same + time as changing the hostname. This is problematic since it + requires a writable /etc file system and is + fragile because the file might be edited by the administrator at + the same time. With nss-myhostname enabled + changing /etc/hosts is unncessary, and on + many systems the file becomes entirely optional. + + To activate the NSS modules, myhostname + has to be added to the line starting with + hosts: in + /etc/nsswitch.conf. + + It is recommended to place myhostname + last in the nsswitch.conf line to make sure + that this mapping is only used as fallback, and any DNS or + /etc/hosts based mapping takes + precedence. + + + + Example + + Here's an example /etc/nsswitch.conf + file, that enables myhostname correctly: + +passwd: compat +group: compat +shadow: compat + +hosts: files dns mymachines myhostname networks: files protocols: db files services: db files -ethers: db files -rpc: db files +ethers: db files +rpc: db files -netgroup: nis - +netgroup: nis - To test, use glibc's getent tool: + To test, use glibc's getent tool: - -$ getent ahosts `hostname` -::1 STREAM omega -::1 DGRAM -::1 RAW + $ getent ahosts `hostname` +::1 STREAM omega +::1 DGRAM +::1 RAW 127.0.0.2 STREAM 127.0.0.2 DGRAM -127.0.0.2 RAW - - - In this case the local host name is omega. - - - - - See Also - - systemd1, - systemd-logind.service8, - logind.conf5, - loginctl1, - pam.conf5, - pam.d5, - pam8, - pam_loginuid8 - - +127.0.0.2 RAW + + In this case the local hostname is omega. + + + + + See Also + + systemd1, + nss-mymachines8, + nsswitch.conf5, + getent1 + +