NIS Binding Problems
Symptoms of NIS Binding Problems
Common symptoms of NIS binding problems include the following.
Messages saying that ypbind can't find or communicate with a server
Commands on a client limp along in background mode or function much slower than normal
Commands on a client hang. Sometimes commands hang even though the system as a whole seems fine and you can run new commands
Commands on a client crash with obscure messages, or no message at all
Problems Affecting Single NIS Client
If only one or two clients are experiencing symptoms that indicate NIS binding difficulty, the problems probably are on those clients. If many NIS clients are failing to bind properly, the problem probably exists on one or more of the NIS servers. See Problems Affecting NIS Clients.
ypbind Not Running on NIS Client
One client has problems, but other clients on the same subnet are operating normally. On the problem client, run ls –l on a directory, such as /usr, that contains files owned by many users, including some not in the client /etc/passwd file. If the resulting display lists file owners who are not in the local /etc/passwd as numbers, rather than names, this indicates that NIS service is not working on the client.
These symptoms usually mean that the client ypbind process is not running. Verify whether the NIS client services are running.
client# svcs \*nis\* STATE STIME FMRI disabled Sep_01 svc:/network/nis/domain:default disabled Sep_01 svc:/network/nis/client:default
If the services are in a disabled state, log in as root or assume an equivalent role, and start the NIS client service.
client# svcadm enable network/nis/domain:default client# svcadm enable network/nis/client:default
Missing or Incorrect NIS Domain Name
One client has problems, the other clients are operating normally, but ypbind is running on the problem client. The client might have an incorrectly set domain.
On the client, run the domainname command to see which domain name is set.
client7# domainname example.com
Compare the output with the actual domain name in /var/yp on the NIS master server. The actual NIS domain is shown as a subdirectory in the /var/yp directory.
client7# ls -l /var/yp -rwxr-xr-x 1 root Makefile drwxr-xr-x 2 root binding drwx------ 2 root example.com
If the domain name returned by running domainname on a machine is not the same as the server domain name listed as a directory in /var/yp, the domain name specified in the machine's /etc/defaultdomain file is incorrect. Reset the NIS domain name as shown in How to Set a Machine's NIS Domain Name.
Note - The NIS domain name is case-sensitive.
NIS Client Not Bound to Server
If your domain name is set correctly, ypbind is running, and commands still hang, then make sure that the client is bound to a server by running the ypwhich command. If you have just started ypbind, then run ypwhich several times (typically, the first one reports that the domain is not bound and the second succeeds normally).
No NIS Server Available
If your domain name is set correctly, ypbind is running, and you get messages indicating that the client cannot communicate with a server, this might indicate a number of different problems:
Does the client have a /var/yp/binding/domainname/ypservers file containing a list of servers to bind to? If not, run ypinit –c and specify in order of preference the servers that this client should bind to.
If the client does have a /var/yp/binding/domainname/ypservers file, are there enough servers listed in it if one or two become unavailable? If not, add additional servers to the list by running ypinit –c.
Do the selected NIS servers have entries in the /etc/inet/hosts file? To view the selected NIS servers, use the svcprop –p config/ypservers nis/domain command. If these hosts are not in the local /etc/inet/hosts file, add the servers to the hosts NIS maps and rebuild your maps by running the ypinit –c or ypinit –s command as described inWorking With NIS Maps.
Is the name service switch set up to check the machine's local hosts file in addition to NIS? See About the Name Service Switch for more information on the switch.
Is the name service switch set up to check files first for services and rpc? See About the Name Service Switch for more information about the switch.
ypwhich Displays Are Inconsistent
When you use ypwhich several times on the same client, the resulting display varies because the NIS server changes. This is normal. The binding of the NIS client to the NIS server changes over time when the network or the NIS servers are busy. Whenever possible, the network becomes stable at a point where all clients get acceptable response time from the NIS servers. As long as your client machine gets NIS service, it does not matter where the service comes from. For example, an NIS server machine can get its own NIS services from another NIS server on the network.
When NIS Server Binding is Not Possible
In extreme cases where local server binding is not possible, use of the ypset command can temporarily allow binding to another server, if available, on another network or subnet. However, in order to use the –ypset option, ypbind must be started with either the –ypset or –ypsetme options. For more information, see the ypbind(1M) man page.
# /usr/lib/netsvc/yp/ypbind -ypset
For another method, see Binding to a Specific NIS Server.
 | Caution - For security reasons, the use of the –ypset and –ypsetme options is not recommended. Only use these options for debugging purposes under controlled circumstances. Use of the –ypset and –ypsetme options can result in serious security breaches because while the daemons are running, anyone can alter server bindings, causing trouble for others and permitting unauthorized access to sensitive data. If you must start the ypbind daemon with these options, after you have fixed the problem you must kill the ypbind process and restart it again without those options.To restart the ypbind daemon, use SMF as follows: # svcadm enable -r svc:/network/nis/client:default |
ypbind Crashes
If the ypbind daemon crashes almost immediately each time it is started, look for a problem in the svc:/network/nis/client:default service log. Check for the presence of the rpcbind daemon by typing the following:
% ps -e |grep rpcbind
If rpcbind is not present or does not stay up or behaves strangely, check the svc:/network/rpc/bind:default log file. For more information, see the rpcbind(1M) and rpcinfo(1M) man pages.
You might be able to communicate with rpcbind on the problematic client from a machine operating normally. From the functioning machine, type the following:
% rpcinfo client
If rpcbind on the problematic machine is fine, rpcinfo produces the following output:
program version netid address service owner ... 100007 3 udp6 ::.191.161 ypbind 1 100007 3 tcp6 ::.135.200 ypbind 1 100007 3 udp 0.0.0.0.240.221 ypbind 1 100007 2 udp 0.0.0.0.240.221 ypbind 1 100007 1 udp 0.0.0.0.240.221 ypbind 1 100007 3 tcp 0.0.0.0.250.107 ypbind 1 100007 2 tcp 0.0.0.0.250.107 ypbind 1 100007 1 tcp 0.0.0.0.250.107 ypbind 1 100007 3 ticlts 2\000\000\000 ypbind 1 100007 2 ticlts 2\000\000\000 ypbind 1 100007 3 ticotsord 9\000\000\000 ypbind 1 100007 2 ticotsord 9\000\000\000 ypbind 1 100007 3 ticots @\000\000\000 ypbind 1 ...
Your system will have different addresses. If the addresses are not displayed, ypbind has been unable to register its services. Reboot the system and run rpcinfo again. If the ypbind processes are there and they change each time you try to restart the NIS service, reboot the system, even if the rpcbind daemon is running.
Problems Affecting NIS Clients
If only one or two clients are experiencing symptoms that indicate NIS binding difficulty, the problems probably are on those clients. See Problems Affecting Single NIS Client. If many NIS clients are failing to bind properly, the problem probably exists on one or more of the NIS servers.
rpc.yppasswdd Considers a Non-Restricted Shell That Begins With r to Be Restricted
Create /etc/default/yppasswdd that contains a special string: "check_restricted_shell_name=1".
If the "check_restricted_shell_name=1" string is commented out, the 'r' check will not occur.
Network or NIS Servers Are Unreachable
NIS can hang if the network or NIS servers are so overloaded that the ypserv daemon cannot receive a response back to the client ypbind process within the timeout period. NIS can also hang if the network is down.
Under these circumstances, every client on the network experiences the same or similar problems. In most cases, the condition is temporary. The messages usually go away when the NIS server reboots and restarts ypserv, when the load on the NIS servers or the network itself decreases, or when the network resumes normal operations.
NIS Server Malfunction
Make sure the servers are up and running. If you are not physically near the servers, use the ping command.
NIS Daemons Not Running
If the servers are up and running, try to find a client machine behaving normally, and run the ypwhich command. If ypwhich does not respond, kill it. Then log in as root on the NIS server and check if the NIS process is running by typing the following:
# ptree |grep ypbind 100759 /usr/lib/netsvc/yp/ypbind -broadcast 527360 grep yp
If neither the ypserv (NIS server) nor the ypbind (NIS client) daemons are running, restart them by typing the following:
# svcadm restart network/nis/client:default
If both the ypserv and ypbind processes are running on the NIS server, then run the ypwhich command. If the command does not respond, the ypserv daemon has probably hung and should be restarted. While logged in as root on the server, restart the NIS service by typing the following:
# svcadm restart network/nis/server:default
NIS Servers Have Different Versions of an NIS Map
Because NIS propagates maps among servers, occasionally you might find different versions of the same map on various NIS servers on the network. This version discrepancy is normal and acceptable if the differences do not last for more than a short time.
The most common cause of map discrepancy is that something is preventing normal map propagation. For example, an NIS server or router between NIS servers is down. When all NIS servers and the routers between them are running, ypxfr should succeed.
If the servers and routers are functioning properly, check the following:
Check the ypxfr log output. See Logging ypxfr Output.
Check the svc:/network/nis/xfr:default log file for errors.
Check the control files. See Check the crontab File and ypxfr Shell Script.
Check the ypservers map on the master server. See Check the ypservers Map.
Logging ypxfr Output
If a particular slave server has problems updating maps, log in to that server and run the ypxfr command interactively. If the command fails, it indicates why it failed, and you can fix the problem. If the command succeeds, but you suspect it has occasionally failed, create a log file to enable the logging of messages. To create a log file, type the following on the slave.
ypslave# cd /var/yp ypslave# touch ypxfr.log
This creates a ypxfr.log file that saves all output from ypxfr.
The output resembles the output ypxfr displays when run interactively, but each line in the log file is time stamped. (You might see unusual ordering in the timestamps. That is okay – the timestamp tells you when ypxfr started to run. If copies of ypxfr ran simultaneously but their work took differing amounts of time, they might actually write their summary status line to the log files in an order different from that which they were invoked.) Any pattern of intermittent failure shows up in the log.
Note - When you have fixed the problem, turn off logging by removing the log file. If you forget to remove it, the file continues to grow without limit.
Check the crontab File and ypxfr Shell Script
Inspect the root crontab file, and check the ypxfr shell script it invokes. Typographical errors in these files can cause propagation problems. Failures to refer to a shell script within the /var/spool/cron/crontabs/root file, or failures to refer to a map within any shell script can also cause errors.
Check the ypservers Map
Also, make sure that the NIS slave server is listed in the ypservers map on the master server for the domain. If it is not, the slave server still operates perfectly as a server, but yppush does not propagate map changes to the slave server.
Workaround to Update Maps on a Broken Slave Server
If the NIS slave server problem is not obvious, you can perform a workaround while you debug the problem, by using the scp or ssh command to copy a recent version of the inconsistent map from any healthy NIS server. The following shows how to transfer the problem map:
ypslave# scp ypmaster:/var/yp/mydomain/map.\* /var/yp/mydomain
The * character has been escaped in the command line, so that it will be expanded on ypmaster, instead of locally on ypslave.
ypserv Crashes
When the ypserv process crashes almost immediately and does not stay up even with repeated activations, the debugging process is virtually identical to that described in ypbind Crashes. First, run the following command to see if any errors are being reported:
# svcs -vx nis/server
Check for the existence of the rpcbind daemon as follows:
# ptree |grep rpcbind
Reboot the NIS server if you do not find the daemon. Otherwise, if the daemon is running, type the following and look for similar output:
% rpcinfo -p ypserver
% program vers proto port service 100000 4 tcp 111 portmapper 100000 3 tcp 111 portmapper 100068 2 udp 32813 cmsd ... 100007 1 tcp 34900 ypbind 100004 2 udp 731 ypserv 100004 1 udp 731 ypserv 100004 1 tcp 732 ypserv 100004 2 tcp 32772 ypserv
Your machine might have different port numbers. The four entries representing the ypserv process are the following:
100004 2 udp 731 ypserv 100004 1 udp 731 ypserv 100004 1 tcp 732 ypserv 100004 2 tcp 32772 ypserv
If there are no entries, and ypserv is unable to register its services with rpcbind, reboot the system. If there are entries, de-register the service from rpcbind before restarting ypserv. To de-register the service from rpcbind, on the server type the following.
# rpcinfo -d number 1 # rpcinfo -d number 2
where number is the ID number reported by rpcinfo (100004, in the preceding example).