"IDENT authentication failed for user" on 7.2.1 but not on 7.1.3

I don't know if this is a bug with PostgreSQL or perhaps
something changed with RedHat 7.3
My application failed on RH 7.3, but worked fine on RH 7.2 & 7.1.
PostgreSQL 7.2.1 produced the following error message:
'FATAL 1: IDENT authentication failed for user "apache"'
but worked okay on PostgreSQL 7.1.3.

Two examples are provided below which demonstrate the problem:
1) NOT okay on RH 7.3, and
2) okay on RH 7.2

1. NOT OKAY ON RH 7.3
*
* $ psql --version
* psql (PostgreSQL) 7.2.1
*
* $ psql octave
* Welcome to psql, the PostgreSQL interactive terminal.
* ...
*
* octave=# \z
* Access privileges for database "octave"
* Table | Access privileges
* -------+--------------------------------
* form | {=,postgres=arwdRxt,apache=rw}
* use | {=,postgres=arwdRxt,apache=rw}
* (2 rows)
*
* octave=# \q
* $ psql -U apache octave
* psql: FATAL 1: IDENT authentication failed for user "apache"

2. OKAY ON RH 7.2
**
** $ psql --version
** psql (PostgreSQL) 7.1.3
**
** $ psql octave
** Welcome to psql, the PostgreSQL interactive terminal.
** ...
**
** octave=# \z
** Access permissions for database "octave"
** Relation | Access permissions
** ----------+-----------------------------------
** form | {"=","postgres=arwR","apache=rw"}
** use | {"=","postgres=arwR","apache=rw"}
** (2 rows)
**
** octave=# \q
** $ psql -U apache octave
** Welcome to psql, the PostgreSQL interactive terminal.
** ...

Any help will be appreciated.
Thanks,
Steve Barker
barkerds@snybufaf.buffalostate.edu
Buffalo State College