It's strange behaviour - series of "cvs checkout" and "cvs rlog" is succesfully made and this exception is thrown.

Job's log:

...
cvs checkout: Updating [dir name]
cvs checkout: Updating [dir name]
...
cvs rlog: Logging [dir/file name]
cvs rlog: Logging [dir/file name]
...
cvs rlog: Logging [dir/file name]
FATAL: CVS authentication failure while running rlog command
java.lang.RuntimeException: CVS authentication failure while running rlog command
at hudson.scm.CVSSCM.getRemoteLogForModule(CVSSCM.java:529)
at hudson.scm.CVSSCM.calculateChangeLog(CVSSCM.java:409)
at hudson.scm.CVSSCM.checkout(CVSSCM.java:829)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1195)
at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:579)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:468)
at hudson.model.Run.run(Run.java:1408)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:238)
Caused by: org.netbeans.lib.cvsclient.connection.AuthenticationException: Timeout, no response from server.
at org.netbeans.lib.cvsclient.Client.ensureConnection(Client.java:418)
at org.netbeans.lib.cvsclient.command.log.RlogCommand.execute(RlogCommand.java:357)
at org.netbeans.lib.cvsclient.Client.executeCommand(Client.java:710)
at hudson.scm.CVSSCM.getRemoteLogForModule(CVSSCM.java:521)
... 9 more

The message further down the stack trace shows the autentication failure as being caused by the server connection timing out. This therefore isn't something that can be fixed with code changes so I'm closing this issue.

That's not as straightforward as it seems - after cvs plugin downgrade to 1.6 and reverting changes in job's configs everything is working fine. So I'm sure that's not problem of timeouts. Eventually this problem may be caused by cvs version we're using.

I've got the same problem since version 2.0 of the plugin.
I've got timeouts randomly. However, the CVS server is available, I can ping it from the jenkins server.

Windows Server 2003 / Glassfish 3.1.2.2 / Oracle SDK 1.7.0_07 / Jenkins 1.486 / CVS Plugin 2.0

Here is the log in the console:

Building in workspace C:\PIC\work\jenkins-work\jobs\OX1_V011703 - etape 02 - TI - CAP\workspace
Using locally configured password for connection to :pserver:hudson@srvcvs1:/cvsroot
cvs checkout -P -r OX1_V011703 -d web src/web
ERROR: CVS Authentication failed: Timeout, no response from server.
org.netbeans.lib.cvsclient.connection.AuthenticationException: Timeout, no response from server.
at org.netbeans.lib.cvsclient.Client.ensureConnection(Client.java:418)
at org.netbeans.lib.cvsclient.command.checkout.CheckoutCommand.execute(CheckoutCommand.java:299)
at org.netbeans.lib.cvsclient.Client.executeCommand(Client.java:710)
at hudson.scm.AbstractCvs$1.invoke(AbstractCvs.java:243)
at hudson.scm.AbstractCvs$1.invoke(AbstractCvs.java:223)
at hudson.FilePath.act(FilePath.java:851)
at hudson.FilePath.act(FilePath.java:824)
at hudson.scm.AbstractCvs.perform(AbstractCvs.java:223)
at hudson.scm.AbstractCvs.checkout(AbstractCvs.java:189)
at hudson.scm.CVSSCM.checkout(CVSSCM.java:318)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1308)
at hudson.model.AbstractBuild$AbstractBuildExecution.defaultCheckout(AbstractBuild.java:679)
at jenkins.scm.SCMCheckoutStrategy.checkout(SCMCheckoutStrategy.java:88)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:584)
at hudson.model.Run.execute(Run.java:1516)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:477)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:236)
ERROR: Cvs task failed
Archiving artifacts
Finished: FAILURE

See https://github.com/jenkinsci/cvsclient/blob/master/src/main/java/org/netbeans/lib/cvsclient/Client.java#L361

This is the method that's causing the error you're seeing whilst it's trying to do it open a connection to the server, with a timeout of 1 minute before failing the connection. If the server fails to accept the connection within this time then the exception you see is thrown. This method doesn't issue any CVS commands, only looks for a network port connection so would be impacted by proxy servers and/or firewall restrictions. Do you have either of these between your Jenkins server and your CVS server?

Note: Pinging your server only shows the network stack is responding, CVS Server sits ontop of this and could be failing to respond whilst the ping command shows the server as being available.

Yes, we have a proxy. I setted up Jenkins to use this proxy in the plugin management, but I added the CVS server hostname in exception list ("No proxy host"). Is the plugin using those settings?

Moreover, we have a strange behavior. When we got this error, if we restart the application server, CVS server is reachable.

CVS plugin doesn't use Jenkins network settings and will only ever attempt a direct connection unless you set values in the CVSROOT entry (CVSROOT supports proxy settings from what I remember but this would be difficult to create automatically from the Jenkins configuration given exclude rules etc).

By 'application server', is this the app server hosting Jenkins? At what point does your issue re-occur (is this random or do you see other issues before hand (hanging jobs, failing jobs etc)? Once the issue does re-occur, do your jobs keep failing until restart or do they recover themselves and, if so, is there a pattern to the recovery (a set time between fail and first recovery, killing selected process on the Jenkins server etc)?