networking - Why is Mac OSX Lion losing login/network credentials?

Symptoms

At work
we have OSX 10.7.3 installed and every once in a while I will see the following
behaviors:

1. If
   the the screen is locked, then multiple tries of the same user/pass are not
   accepted.




2. If the screen is unlocked,
   then opening a new bash term may yield prompts such
   as:

   
   
   

   `I have no
               name$`
   

   
   
   

   or

   
   
   

   lkyrala$
               ssh lkyrala@ah-lkyrala2u 
   You don't exist, go
               away!
   
   

Even
when our Macs are working normally, everyone here has to log in twice. The first time
after boot always fails, but the second time (with the same
password, not changing anything, just pressing enter again) succeeds.
Weird?

Workarounds

There
are some workarounds that resolve the immediate problem, but don't prevent it from
happening
again:

1. wait
   (maybe an hour or two) and the problems sometimes go away by
   themselves.




2. kill 'opendirectoryd' and
   let it restart. (from rel="nofollow noreferrer">Apple Support Communities: User ID (not data) deleted
   suddenly?)




3. hold the power
   button to reset the
   computer

UPDATE
10/4/2012

Our net admins suspect that lockd is
implicated. lockd apparently uses UDP and when the network is congested, packets are
lost, which results in the hanging behavior. They are looking at steps to decrease the
congestion. If the file access in question happens to be the Active Directory
authentication handle, then all of these different pieces start to fit
together.

Discussion

Now,
the evidence above points me to something screwy with opendirectory and login
credentials. Some other people report having these login problems, but it's hard to
determine where the actual problem is (Mac, or network environment?).

I should add that most of the network are
Windows machines, but we have quite a few Macs and Linux machines as well, but I'm not
sure of the details of how the network auth is mapped from various domains to others...
all I know is that our network credentials work in Windows domains as well as mac and
linux logins -- so something is connecting separate systems, or using the same global
auth system.

Additional
Detail

Unfortunately, I didn't set up this Mac,
our IT dept did, so I'm not entirely sure how authentication works. I do know that it is
a network login (which is unusual in my experience with Macs, they usually have local
accounts which connect to external resources) but here, our home folder is on the
network, not local. Under my linux installs, connecting to the network involves yp/NIS,
(which allows us to automount parts of our network filesystem from any machine), and the
opendirectoryd.log seems to confirm this is
involved...

/var/log/opendirectoryd.log*
shows:

2012-04-04
            01:29:12.370 EDT - ddddd.dddddd.dddddd.dddddd - Client: automount, UID: 0, EUID: 0, GID:
            0, EGID: 0
2012-04-04 01:29:12.370 EDT - ddddd.dddddd.dddddd.dddddd, Node:
            /NIS/Domain, Module: nis - could not determine map for rectype 'mounts' attribute
            'byname'
2012-04-04 01:32:04.504 EDT - failed to get YP map
            list

It looks like the
domain 'Domain' is being lost somehow. Why is the UID == 0 here? That seems bad, doesn't
it?

I know under Linux a while back, I
discovered that the NIS broadcast had been disabled or blocked, so I gathered the IPs
from someone and set the ypserver IPs manually in /etc/yp.conf
and that fixed drops in Linux. Maybe something similar is going on
here?

I tried looking up information
in Mac's yp man pages:

And then found this post
detailing where the existing servers are
set:

However, checking the
ypserver settings showed that both server IPs were correctly set for
NIS.

Checking
/var/log/system.log
shows:

Aug 28 00:30:08 mymac
            ypbind[22991]: direct: sendto: No route to host
Aug 28 00:30:08 mymac
            ypbind[22991]: direct: sendto: No route to host
Aug 28 00:30:08 mymac
            ypbind[22991]: Can't contact any servers listed in /var/yp/binding/Domain.ypservers.
            Aborting
Aug 28 00:30:08 mymac com.apple.launchd[1]
            (com.apple.nis.ypbind[22991]): Exited with code: 1
Aug 28 00:30:08 mymac
            com.apple.launchd[1] (com.apple.nis.ypbind): Throttling respawn: Will start in 10
            seconds
Aug 28 00:30:08 mymac xpchelper[22990]: getpwuid_r() failed for UID:
            uuuu, ret: 0, errno:
            0

So this
makes me suspect the nfs.conf settings, etc. Some others believe that this is due to
something in
lockd.

Research

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