Other network questions on TUONET

Last modified by on 29.08.2017 12:43



I need to call via VoIP from my computer.
You can choose one of these VoIP external providers in TUONET network:

  • 802.cz
  • sip.odorik.cz
  • sip.mujtelefon.cz
  • sip.viphone.cz
    If you want to use other provider, please let us know via helpdesk.


I would like to watch multicast transmission of the seminar with VLC player
This problem can be caused by firewall. Try to shut firewall down and transfer should work.
Problem could be also in VLC program, or in its current version which could not work well at university network. Try to download and install older version. If the school playlist does not work anyway then nothing prevents you from using your own playlist. 



How is network traffic filtered?
University network is protected by stateful firewall where standard policy is set up that all accesses outside-inside are (there are exceptions) blocked and all accesses inside-outside are (there are exceptions too) allowed. For full access to the university network use VPN.

On the network perimeter are blocked protocols NetBIOS, SMTP (TCP/25), DNS (TCP,UDP/53). For technical reasons it is not possible to you IPsec VPN, use SSL VPN protocols.

Between networks from users accomodated at dormitory and university network NetBIOS protocols are filtered. Access to centralized file servers (for example HOMEN) is allowed.



I cannot get NTP working
Pokud se Vám synchronizace nedaří, vyzkoušejte tento postup:

  1. Turn firewall off.
  2. Restart computer.
  3. Confirm settings and synchronization with button update according to the guide.
  4. Turn firewall on again.
  5. Following sychronizations will be automatic.


Some pages do not load on Mac OS X
Problem can be in the network with direct support of protocol IPv6 where is computer moved to (for example in sleep mode) in which system created automatic tunnel for supporting protocol IPv6. During shifts of turned on computers from one network to another one some steps essential for correct finish of the created tunnel can´t be properly done and it may happen that configuration via autoconfiguration mechanisms of protocol IPv6 is not performed correctly.
Solution:
Solution is forced shut down and turn off  of protocol IPv6 on every network interface possibly restart the computer.

Turning the terminal on
Go → Utilities → Terminal

Undesirable state (unavailable pages of Google):

$ ping6 google.com
ping6: UDP connect: No route to host

To remove the problem admin authorization is required:

$ sudo -s

Turning IPv6 off on all network interfaces:

# ip6 -x

Turning IPv6 on again on all network interfaces:

# ip6 -a

Possible performance of both commands at once:

# ip6 -x && ip6 -a

Correct state:

$ ping6 google.com
PING6(56=40+8+8 bytes) 2001:718:1001:158:20c:29ff:fec8:e4a4 > 2a00:1450:8007::68
16 bytes from 2a00:1450:8007::68, icmp_seq=0 hlim=57 time=21.751 ms
16 bytes from 2a00:1450:8007::68, icmp_seq=1 hlim=57 time=15.811 ms
16 bytes from 2a00:1450:8007::68, icmp_seq=2 hlim=57 time=15.859 ms
^C
- google.com ping6 statistics -
3 packets transmitted, 3 packets received, 0.0% packet loss
round-trip min/avg/max/std-dev = 15.811/17.807/21.751/2.789 ms

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