Network and DNS Setup Issues

Question

I am setting up an Xserv with Snow Leopard at my school, and I'm running into DNS issues.
I followed the excellent guide at http://labs.hoffmanlabs.com/node/1436 and believe I've set DNS up correctly, but I fail the changeip -checkhostname test (I've replaced my domain and server names):
mserver:~ admin$ sudo changeip -checkhostname
Primary address     = 10.10.10.2
Current HostName    = myserver.mydomain.ns.ca
DNS HostName        = myserver
To fix the hostname please run /usr/sbin/changeip for your system with the
appropriate directory with the following values
   /usr/sbin/changeip 10.10.10.2 10.10.10.2 myserver.mydomain.ns.ca myserver
dirserv:success = "success"
I tried running the command as given, ("sudo /usr/sbin/changeip 10.10.10.2 10.10.10.2 myserver.mydomain.ns.ca myserver") but that didn't solve it. I'm not sure if that's the correct thing to do, or why that didn't work.
I have come to suspect that my issue is with network settings, and would appreciate advice on what I'm trying to do. The server (our only one) will be an OD master, a file server and a web server. It is inside our router, with an externally-reachable IP address and an internal one (the latter is 10.10.10.2). I have configured it with the two IPs on one port to avoid the issue with SL wanting two serial numbers. My System Preference > Network settings are as follows:
Ethernet 1b (highest service order):
IP Address: 10.10.10.2
Subnet mask: 255.255.255.0
Router: 10.10.10.1
DNS Server: 127.0.0.1
Search Domains: mydomain.ns.ca
Ethernet 1 (second highest service order):
IP Address: <my external IP>
Subnet mask: 255.255.255.248
Router: <my ISP's router>
DNS Server: 127.0.0.1
Search Domains: mydomain.ns.ca
Ethernet 2:
Not Connected
Although I'm unsure what it means (I'm more a teacher than a techie!), Server Admin > Settings > Network shows:
Computer Name: myserver
Local Hostname: myserver
Network Interfaces:
en0; IPv4; 10.10.10.2; myserver.mydomain.ns.ca
Ethernet 1 (en0); IPv4; <my external IP>; myserver.local
The second of the interfaces above is bold.
The big issue I'm seeing on my network (possibly as a result of this, but everything I've seen says fix DNS first) is that network users can't log in although they have homes and can connect to the homes once logged in as local users.
Many thanks in advance for your help--the school year is closing in quickly!
Regards,
Alex

Answer 1

Thanks. I disabled the external IP & rebooted. Server Admin now has only the one IP. But I still get the same result:
myserver:~ admin$ dscacheutil -flushcache
myserver:~ admin$ sudo changeip -checkhostname
Password:
Primary address     = 10.10.10.2
Current HostName    = myserver.mydomain.ns.ca
DNS HostName        = myserver
To fix the hostname please run /usr/sbin/changeip for your system with the
appropriate directory with the following values
   /usr/sbin/changeip 10.10.10.2 10.10.10.2 myserver.mydomain.ns.ca myserver
dirserv:success = "success"
myserver:~ admin$
I ran dig on a client:
Last login: Mon Sep  5 11:40:13 on console
Lab-iMac-64:~ admin$ dig myserver.mydomain.ns.ca
; <<>> DiG 9.6.0-APPLE-P2 <<>> myserver.mydomain.ns.ca
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 45308
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;myserver.mydomain.ns.ca.        IN    A
;; AUTHORITY SECTION:
mydomain.ns.ca.        10800    IN    SOA    myserver.mydomain.ns.ca. dns.mydomain.ns.ca.mydomain.ns.ca. 2011090201 86400 3600 604800 345600
;; Query time: 1 msec
;; SERVER: 10.10.10.2#53(10.10.10.2)
;; WHEN: Mon Sep  5 11:40:42 2011
;; MSG SIZE  rcvd: 94
Lab-iMac-64:~ admin$ dig -x 10.10.10.2
; <<>> DiG 9.6.0-APPLE-P2 <<>> -x 10.10.10.2
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7073
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;2.10.10.10.in-addr.arpa.    IN    PTR
;; ANSWER SECTION:
2.10.10.10.in-addr.arpa. 10800    IN    PTR    myserver.
;; AUTHORITY SECTION:
10.10.10.in-addr.arpa.    10800    IN    NS    myserver.mydomain.ns.ca.
;; Query time: 3 msec
;; SERVER: 10.10.10.2#53(10.10.10.2)
;; WHEN: Mon Sep  5 11:41:04 2011
;; MSG SIZE  rcvd: 99
What to try next?
~Alex
PS- ...and I'm still not able to log in as a network user, but still can access network accounts using connect to server. Here's what my password log looks like when I try to log in (hash and username edited):
Sep  5 2011 11:34:11    RSAVALIDATE: success.
Sep  5 2011 11:34:11    AUTH2: {0x4e4d1b4e67..., alex} DHX authentication succeeded.
Sep  5 2011 11:34:11    KERBEROS-LOGIN-CHECK: user {0x4e4d1b4e67..., alex} is in good standing.
Sep  5 2011 11:34:11    KERBEROS-LOGIN-CHECK: user {0x4e4d1b4e67..., alex} authentication succeeded.
Sep  5 2011 11:34:11    GETPOLICY: user {0x4e4d1b4e67..., alex}.
Sep  5 2011 11:34:11    GETPOLICY: user {0x4e4d1b4e67..., alex}.