Repeated ORA-12547 Messages after installing Oracle 10g

Question

Hi,
I installed Oracle 10g on a Redhat ES 3 box, and the install went okay, but when I try and interact with the server I get the message:
ORA-12547: TNS: lost contact
For example, if I use the Database Configuration Assistant to attempt to create a database, I will see the above message when it begins the database creation process, or if I try to interact with the Oracle server using sqlplus I will see the above message after each command entered.
I had recently tried to install Oracle 8.1.7 on the same box, but abandoned that after deciding that the effort required to link Oracle 8 on RHES3 just wasn't worth it. I have been told that this previous partial installation may be the cause of the problem, and have been advised to uninstall Oracle 8, uninstall Oracle 10g, and reinstall Oracle 10g. I find it hard to believe that it would require such an action to solve this problem. Is there any configuration changes I can make to resolve it? Also, what does this message actually mean?
I am new to Oracle, so thanks for any help with this problem.
Colm.

Answer 1

My last message asking for a grater degree of specificity was not overly specific, hence I am posting the kernel parms that I have set with the hopes that you will spot one that I set improperly or one that I neglected to set.
[root@awyr ~]# cat /proc/sys/kernel/shmmax
2147483648
[root@awyr ~]# cat /proc/sys/kernel/shmmni
4096
[root@awyr ~]# cat /proc/sys/kernel/shmall
2097152
[root@awyr ~]# ipcs -lm |grep "min seg size"
min seg size (bytes) = 1
[root@awyr ~]# cat /proc/sys/kernel/sem | awk '{print $1}'
250
[root@awyr ~]# cat /proc/sys/kernel/sem | awk '{print $2}'
32000
[root@awyr ~]# cat /proc/sys/kernel/sem | awk '{print $3}'
100
[root@awyr ~]# cat /proc/sys/kernel/sem | awk '{print $4}'
128
[root@awyr ~]# cat /proc/sys/fs/file-max
65536
[root@awyr ~]# cat /proc/sys/net/ipv4/ip_local_port_range
1024 65000
[oracle@awyr Desktop]$ ulimit -n
63536
[oracle@awyr Desktop]$ ulimit -u
4091
[oracle@awyr Desktop]$ ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
file size (blocks, -f) unlimited
max locked memory (kbytes, -l) 32
max memory size (kbytes, -m) unlimited
open files (-n) 63536
pipe size (512 bytes, -p) 8
stack size (kbytes, -s) 8192
cpu time (seconds, -t) unlimited
max user processes (-u) 4091
virtual memory (kbytes, -v) unlimited
from sysctl -a
my fs.file-max = 65536
in my limits.conf I added:
oracle soft nofile 4096
oracle hard nofile 63536
in my (1) /etc/pam.d/system-auth (2) /etc/pam.d/sshd (3) /etc/pam.d/su (4) /etc/pam.d/login
files I added:
session required pam_limits.so
and verified that it exists
in my limits.conf I added
oracle soft nproc 2047
oracle hard nproc 16384
my /etc/oratab has:
orcl:/usr/local/oracle/app/oracle/oracle/product/10.2.0/db_1:N
I tried to change the N at the end to a Y but to no avail
my /etc/oraInst.loc has:
inventory_loc=/usr/local/oracle/app/oracle/oraInventory
inst_group=oinstall
Thanks again for your atention
Richard