Red Hat Bugzilla – Bug 8456
Problem with gethostid system call
Last modified: 2008-05-01 11:37:53 EDT
The gethostid system call returns the wrong host id. The default 6.1 version of the /etc/hosts file is different from the default version for 6.0 and earlier. If it is left alone, then the gethostid call returns the wrong IP address (127.0.0.1). If it is rewritten to be the same as version 6.0 and earlier then gethostid returns the correct value. 6.1 version: 127.0.0.0 localhost.localdomain localhost myname www.xxx.yyy.zzz localhost.localdomain 6.0 version 127.0.0.1 localhost localhost.localdomain www.xxx.yyy.zzz myname.mydomain myname Oddly enough if I use the 6.1 format on my 6.0 machine, gethostid works correctly.
Do you mean gethostid or (more likely) gethostbyname? If the latter, simply edit /etc/hosts and configure it correctly. The installer has heuristics that, depending on the hardware and how the questions were answered, will lead to differences in the "default" /etc/hosts. Gethostid on the other hand is a silly system call that simply returns whatever was set by sethostid (so I don't think that's what you meant).
Sorry but I believe that this is a bug and the resolution provided is not adequate. One of the primary uses for the gethostid call is to return a unique id. The problem with the proposed resolution is that unless somebody edits the /etc/hosts and changes the layout then many systems will have the same hostid, i.e. based on 127.0.0.1. The gethostid call is very often used for licensing software purposes on other OS's such as Solaris. In fact the gethostid call returns the MAC address on many OS's rather than the IP address. For vendors providing software that uses licensing it makes life very difficult if they have to ask the customer to edit system files to get a unique ID returned so they can issue a licence. IMHO gethostid should return a MAC address and not an IP since MAC addresses are unique (as far as I know) . If this is not possible then at lease gethostid should return a IP that is not the local loopback one.