Secondary group info source

Experts,

I know when I use id it shows only the primary group information for the given user, and that info comes from passwd file. When I use groups it shows all groups user are member of, however from where come information given by groups command?

grep fmtt3990 /etc/passwd
fmtt3990:x:261869:1500:Felipe Mattos:/home/fmtt3990:/usr/bin/ksh

groups fmtt3990
osadmins vrtadm usaudit

id fmtt3990
uid=261869(fmtt3990) gid=1500(osadmins)

Thanks in advance.

/etc/groups

Bartus11,

Right after I posted it I realized the dummy question I made; in fact in almost all machines I own what you said is true, however only on this one, from where I took the info to paste here that isn't. Wonder why is this machine different from all others on my organization. There is another place that it can be stored?

egrep "(osadmins|vrtadm|usaudit)" /etc/group
osadmins::1500:
vrtadm::11433:
usaudit::508:

Thanks.

It might be in a NIS, NIS+ or LDAP group map.

How do I check that? I'm on task to standardize all Unix access on my organization, want to have all servers with same template.

Thanks.

That command will tell you where the group maps are coming from:

grep "^group" /etc/nsswitch.conf

Oh yeah! Hot diggity! Now I see how it is configured. Makes me wonder why it is not documented on our server history database, I'm going to nag on my engineers. =)

Thanks everyone by the help.