Ok. Quick update. One of my samba logs (/var/log/samba/log.10.1.1.132) just filled up with a bunch of stuff:
These are repeated for several lines (about 20 repeats of those two lines with only the time changing). 10.1.1.132 is the machine that I've been trying to get to join the domain.

I hope you are not trying to get XP Home Edition in a domain... you cannot get a PC with XP Home Edition to join a domain.
I also hope that you checked your third-party (not Windows default firewall) firewall that you maybe installed by yourself a while ago and forgot about it, or your ISP gave you a trial/express edition of a firewall that you just overlooked while picking through log files...

It is XP Pro SP2.
Our company uses all Windows clients running Zone Alarm for AV, Firewall, Spam filter, YADA, YADA, YADA. I have uninstalled it from the test system for the time being to make sure it's not interfering with the network communications.

The Debian install was a minimal install (not even a GUI) with packages added after the OS was fully installed. So far only DNS (bind9) has been installed and configured to work on our network. Once I get Samba working, Exim4 will be the last thing to install and configure for this server (as far as server services goes anyways). I have not found any information one way or the other on what firewall Debian might have installed during it's setup, but I have checked and am unable to find a PID for one running.

I notice you have root denied in the global settings, I wonder if that is stopping the machine from authenticating properly. Since it is denying root from connecting to samba, maybe try commenting it out for now and if it works just uncomment it once all the machines are connnected.

Comparing your smb.conf with the mine, I've found some diferences that could help you:

#### Networking ####

# The specific set of interfaces / networks to bind to
# This can be either the interface name or an IP address/netmask;
# interface names are normally preferred
# In this case substitute 172... with your IP range and device
# This option enable samba to listen for connections
interfaces = 172.26.0.0/255.255.0.0 eth0

# Is this machine able to authenticate users. Both PDC and BDC
# must have this setting enabled. If you are the BDC you must
# change the 'domain master' setting to no
#
domain logons = yes
#

This is for domain logons :

# The following setting only takes effect if 'domain logons' is set
# It specifies the location of the user's profile directory
# from the client point of view)
# The following required a [profiles] share to be setup on the
# samba server (see below)
logon path = \\%N\profiles\%U
# Another common choice is storing the profile in the user's home directory
logon path = \\%N\%U\profile

# The following setting only takes effect if 'domain logons' is set
# It specifies the location of a user's home directory (from the client
# point of view)
logon drive = H:
logon home = \\%N\%U

Could be important :

# Most people will find that this option gives better performance.
# See smb.conf(5) and /usr/share/doc/samba-doc/htmldocs/speed.html
# for details
# You may want to add the following on a Linux system:
# SO_RCVBUF=8192 SO_SNDBUF=8192
socket options = TCP_NODELAY

I've nor use the host allow option in Samba. I've use /etc/host.allow for give access permissions.

Well, that's all. Hope it helps.

er......
What I know about this issue would fit behind a ferret's foreskin - but....

smb passwd file = /etc/samba/smbasswd??

B.

I commented out that line and saw no improvement. I was under the impression that the purpose of that line is to keep a user (admin included) from logging into a domain workstation with the root account. I did not think that it was a factor in the initial authentication for joining a machine to the domain. I haven't found any info one way or the other on that, so if anybody knows for certain, please post.
I tried those changes and have not had any luck so far. I'm kinda thinking DNS crapped out on this thing.
I completely missed that typo. Good eye for picking it up.

I am starting to suspect DNS because my clients are no longer able to see this server on the network. I can ping it from any client, but cannot browse to it using Explorer (not IE). I will post whatever I find regarding this issue. Thanks for everyone's help so far.

Isn't that just typical. DNS was kludged. I got it working and suddenly, Samba is in great shape. I can join the domain, run login scripts, share files and just have an all around good time. Thank you everyone for your help. I could not have gotten it working without all the excellent advice and leads.

Yeah stops anyone logging in through the root account, just wasn't sure if it affected the initial authentication since only root can add a machine to the domain, once the machine is added then any user can then log into the domain. Although you did create the initial account so probably didn't make a difference.

Good to hear it's all up and running, DNS can be fun sometimes. Glad to have help

have you try, to enter the as Username, the XP User you are loging with, and that Password ??

This entire thread seems to describe the problems I'm having trying to join my XP machine to Samba.

I'm not sure what you meant or how you got DNS working?

I'll clarify "kludged" for you then.

I had installed bind9 on this server for DNS. Unfortunately, several of the configuration files for the main zone and reverse zones had typos and little hard to find mistakes in them. After going through all of the configuration files and correcting those mistakes, DNS then started working to resolve domain names. As an alternative, you can setup a cacheing only DNS server using the example provided here on the bind9 website (offsite link).

If you need more help then that, feel free to post your smb.conf here.

Just a quick note, you don't have to have a DNS server running to have clients connect to a samba domain controller.