Rešavanje problema

Important

If you encounter interaction or connection problems between master and client computers you should always ensure that an identical Veyon configuration is used on all computers. To avoid problems in general it’s recommended to automate the configuration transfer during installation or via the Interfejs komandne linije instead of importing the configuration manually using the Veyon Configurator. The configuration must also be transferred to all affected computers each time a change is made during troubleshooting.

Onemogućen pristup kompjuterima

There are multiple causes which can prevent access to a computer using Veyon Master.

Mrežni problemi

First of all the general network connectivity of the computer should be checked. Use the utility ping (which is usually included with every operating system) to diagnose connectivity problems.

Problemi sa Veyon Service-om

If the computer can be pinged you should verify that the Veyon Service is running correctly. Open the Veyon Configurator and open the configuration page Servis. In the section Opšte the status of the service should be displayed with status Running. Otherwise the service can be started using the button Start service. If this is not successful you should try reinstalling Veyon. If a new installation does not help you can check the log files of the Veyon Service as well as the logging messages of the operating system for error messages and possible causes. Additionally you can find more hints or settings in the service management of your operating system.

Postavke servisa i firewall-a

If the service is running you have to ensure that it is listening for incoming connections on the correct network port. You can verify that on the local computer using telnet:

telnet localhost 11100

Besides general program output the character string RFB 003.008 must be displayed. If the output does not contain these characters you should check the network port number settings and Miscellaneous network settings, especially the Veyon server port number. You should try to reset them to their default values.

Next the same access has to be possible from a different computer in the network. The utility telnet can be used again for the diagnosis. The program argument localhost has to be replaced with the name or IP address of the corresponding computer. If the access fails please ensure that the option Allow connections from localhost only in the Miscellaneous network settings is disabled. Additionally computer access control should be disabled initially as the service otherwise might listen on localhost only. This can happen if the external access would be denied because of currently matching rules. If both settings are correct the output of

netstat -a

has to indicate that the service is not (only) listening on localhost or 127.0.0.1 (status LISTEN or similar).

If the port access from remote computers still fails usually a firewall prevents the access and has to be reconfigured accordingly. On Linux this concerns settings of iptables, ufw etc. Consult the corresponding manuals of the used software. On Windows Veyon automatically configures the integrated Windows firewall if the option Enable firewall exception in the Miscellaneous network settings is set to its default value (enabled). If a 3rd party firewall solution is used it must be configured to allow external access to TCP ports 11100 (Veyon server port) and 11400 (demo server).

Postavke autentifikacije

Another cause of the error can be wrong or insufficient authentication settings. For first tests you should select logon authentication instead of key file authentication on both computers. As soon as the authentication test is successful on the local computer external access will also work.

If key file authentication is used the key files on master and client computers must match exactly. On client computers the public key file must have exactly the same content as on the master computer. If the access still fails the access permissions to the key files may be wrong. The Veyon Service needs to have read permissions on the public key file while the user of Veyon Master has to be able to read the private key file. If the problem persists the key file directories of the key files should be deleted on all computers and a new keypair generated on the master computer. The public key must then be imported again on all client computers.

Postavke za kontrolu pristupa kompjutera

An incorrect configuration of computer access control can also lead to computers being inaccessible. Initially it’s recommended to disable computer access control completely using the Veyon Configurator. This allows determining which method for computer access control is possibly incorrectly configured.

If authorized user groups for computer access are used you should check whether the list of authorized user groups is complete and whether the accessing user is a member of one of these user groups.

Improperly configured access control rules can also cause problems with accessing computers. It is necessary to always specify at least one rule to allow access under certain conditions. If this is ensured, a temporary test rule can be inserted at the end of the list for further debugging. This rule should be configured so that the option Always process rule and ignore conditions is enabled and the action Allow access is selected. This rule can then be moved up in the rule list step by step until the test returns the desired positive results and the access works. The access rule located directly below the test rule is then the cause for the access denial and can be examined more closely and corrected accordingly. Don’t forget to remove the test rule afterwards to prevent unauthorized access.

Anti-virus software

It has been reported by some users that an installed anti-virus software caused problems with Veyon, especially regarding the Veyon Service. As part of the troubleshooting process you should temporarily disable the anti-virus software in order to figure out whether the anti-virus software is the cause of error. If so, try to add an exception for the Veyon Service after enabling the anti-virus software again. Alternatively contact the vendor of your anti-virus software for further assistance.

Time synchronization problems

When using logon authentication, Veyon requires the operating system to reliably perform user authentications on all remote computers. Especially in AD/Kerberos-based environments, authentication may not work reliably when the system clock is not synchronized with the domain controller or authentication server and differs significantly. Therefore make sure time synchronization is configured and working properly if you encounter sporadic connectivity problems when using Veyon.

Postavke nisu korektno snimljene/učitane

Nakon ažuriranja na novu verziju Veyon-a u retkim slučajevima se može dogoditi da neki konfiguracioni ključevi budu nedosledni i da ih treba ponovo stvoriti. To može rezultirati da se podešavanja ne sačuvaju ili ponovo učitaju, poput ugrađene lokacije i informacija o računaru. U ovom slučaju configuration should be reset će ponovo izgraditi na osnovu zadanih vrednosti.

Lokacije i kompjuteri iz LDAP direktorija nisu prikazani u Veyon Master-u

Molim budite sigurni da:

  • network object directory na konfiguraciskoj stranici General je postavljen na LDAP Basic ili LDAP Pro
  • LDAP testovi integracije List all entries of a location i List all locations su uspešni i vraćaju ispravne objekate
  • na konfiguracijskoj stranici Master sve opcije za fino podešavanje ponašanja su postavljene na zadane vrednosti

Odabir trenutne lokacije automatski ne radi

Ako je aktivirana opcija option automatically selecting the current location , ali nema efekta prilikom pokretanja Veyon Master-a, prvo trebate biti sigurni da je glavni računar takođe naveden kao računar za odgovarajuću sobu u network object directory.

Ako problem i dalje postoji iako su svi unosi u direktoriju mrežnih objekata tačni, obično postoji problem sa DNS konfiguracijom u mreži. Proverite da li se računarska imena mogu razrešiti sa IP adresama, a obrnutim pregledima IP adresa vratiti odgovarajuća imena računara. Na većini operativnih sistema je DNS dijagnostički alat nslookup dostupan za ovu svrhu. Pozivanje programa sa nazivom lokalnog računara kao argumenta mora vratiti važeću IP adresu. Drugi poziv sa određenom IP adresom mora ponovo da vrati ime računara.

Ako funkcija ne radi po želji uprkos ispravnom podešavanju DNS-a, u drugom koraku log level može se postaviti na najveću vrednost (Debug messages and everything else). Nakon ponovnog pokretanja Veyon Master-a, možete potražiti log fajl VeyonMaster.log u the log file directory za daljnje uzroke grešaka. Redovi s porukama „initializing locations” i „found locations” označavaju koja su imena hosta i IP adrese korištena za određivanje lokacije i koje su lokacije na kraju određene na osnovu tih informacija.

Zaključavanje ekrana može biti preskočeno sa Ctrl+Alt+Del

Da biste u potpunosti blokirali sve pritiske na tastere i prečice na tastaturi u režimu zaključavanja ekrana, morate ponovo pokrenuti računar nakon instaliranja Veyon-a na Windows-e. Bez ponovnog pokretanja, Veyon-ov drajver za uređaje za unos još uvek nije aktivan i ne mogu se presretati pritisci tastera.

U demo režimu se na klijentskim računarima prikazuje samo crni ekran ili prozor

Molim budite sigurni da:

  • in the configuration page Service under network port numbers the demo server port is set to its default value 11400
  • na stranici za konfiguraciju Service firewall izuzetak je omogućen na glavnom računaru ili je firewall drugog proizvođača konfigurisan da dopušta dolazne veze na TCP port 11400
  • korisnik Veyon Master-a ima pristup svom računaru (tj. lokalnom Veyon servisu). U access control ruleset može postojati pravilo koje zabranjuje pristup računaru ako je učitelj prijavljen. U ovom slučaju trebalo bi da stvorite pravilo sa uslovom Accessing computer is localhost omogućen što je moguće više u listi pravila. Inače demo server ne može pristupiti ekranu sadržaja nastavničkog računara i distribuirati ga na računare klijenta.

Veyon Server pada uz XIO ili XCB greške na Linux-u

Poznati su problemi sa specifičnim verzijama KDE i Qt na Linux-u koji su uzrokovali pad sistema Veyon Server-a. Povezano je i sa nekoliko drugih implementacija VNC servera. Ako ste pogođeni takvim padovima Veyon-a, razmotrite nadogradnju KDE/Qt. Kao krajnje sredstvo možete onemogućiti X Damage ekstenziju u konfiguraciji VNC servera. To će, međutim, smanjiti ukupne performanse i povećati opterećenje CPU-a.