CityLink FAQs & Help

The following information will help CityLink resolve your fault more quickly:

• Your business name as it appears on your CityLink invoice.
• Your physical location, including building name if known.
• The service affected (e.g. PublicLAN, PrivateLAN, FibreLINK, etc)
• The circuit ID of the affected service (WC# / AC#).
• A detailed description of the fault, including when the issue started.
• Who your ISP is if the affected service is a PublicLAN connection.

It's also worth remembering that CityLink is not an ISP. CityLink generally only provides the "last mile" connection.

This means that a fault like "I can't reach Google but Trade Me is working fine" is most likely to be an issue with your ISP.

View the Network status page

CityLink provides a server for http://speedtest.net. You can test your Internet connection against our server by selecting "Wellington, New Zealand" from the map.

Not by CityLink, but possibly by your ISP. Check with your ISP for their charging policy.

CityLink implements a BPDU guard on all ports. For an in depth discussion of this see http://news.clnz.net/2008/11/19#November-Faults .

If you connect equipment to the CityLink network that is sending Spanning Tree BPDU's then it's likely that the network will react by disabling your port briefly. After a short delay the network will re-enable the port. If your equipment continues to send BPDU's then the port will be disabled again. The port will appear to flap approximately once per minute. The remedy is to disable Spanning Tree on the port facing CityLink.

See "Useful Config Statements" below for help preventing a switch from sending Spanning Tree BPDU's.

If you require Spanning Tree (for example, you connect to CityLink in multiple locations and you rely on Spanning Tree to prevent loops) or you are unable to disable Spanning Tree please contact CityLink to discuss (tech@citylink.co.nz).

CityLink recommends connecting your router/firewall directly to your CityLink port. If you have installed a switch between your router/firewall and the CityLink port, or you are using a "Layer 3" switch then you may be affected by Loopback errors.

Most Cisco switches use a feature Loopback detection to protect themselves from loops in an Ethernet network. When a large Ethernet network like CityLink's has a failure, it is possible for the Loopback detection mechanism to be triggered. Your equipment will typically err-disable the port facing CityLink and report a Loopback fault in the logs. The real issue is that the switch won't enable the port again when the fault in the network is fixed.

On a Cisco switch the following commands will cause the switch to re-enable the port automatically after 5 minutes.

errdisable recovery cause loopback 
errdisable recovery interval 300

The AMS-IX (http://www.ams-ix.net/config-guide/) provide an excellent reference for configuring edge devices.

The following are example commands for a Cisco device:

! Global commands

! automatically recover from loopback errors
errdisable recovery cause loopback
errdisable recovery interval 300

! Layer 2 Interface commands
interface gigabitethernet XXXX

! disable DTP negotiation
switchport nonegotiate

! disable CDP
no cdp enable

! disable loopback packets
no keepalive

! disable udld
no udld enable

! disable lldp
no lldp receive
no lldp transmit

! discard spanning-tree
spanning-tree bpdufilter enable

! Layer 3 Interface commands
interface vlan XXXX or interface gi XXXX

! ignore icmp redirect packets
 no ip redirects

! disable proxy arp
no ip proxy-arp

! ignore directed broadcast packets
no ip directed-broadcast

If you have any questions about the right way to configure a device please contact CityLink to discuss your requirements (tech@citylink.co.nz).

PublicLAN and ExchangeNET are best effort only services.

PrivateLAN is a guaranteed bandwidth service. We don't support QoS but guaranteed bandwidth provides a suitable alternative to QoS. DiffServ markings are preserved so end-to-end QoS is still possible.

Dark Fibre is only limited by your equipment.

For further information on why we believe QoS in not the answer, please contact the CityLink Tech Team.

See http://nzix.net/why.html.

Select the exchange of interest from the main page and complete the application form.

Select the exchange from the main page then select "Change XXX Routes" or "Change XXX Route Filters".

All of the exchanges operate a looking glass (http://nzix.net/cgi-bin/lg.cgi)

Currently only the Auckland and Wellington exchanges support IPv6.

CityLink provides a mailing list for notifications of outages.

Sign up to receive network event updates via email.

The CityLink Tech Team write a blog (http://news.clnz.net) where we post information that we think our customers may find interesting or useful. The posts tend to be fairly technical and informal.

The NZNOG (New Zealand Network Operators Group) mailing list (http://list.waikato.ac.nz/mailman/listinfo/nznog) is another excellent source of information. We recommend this list for customers participating in any of the NZ Internet Exchanges (http://nzix.net) or anyone with an interest in the NZ Internet scene.

The CCIP (Centre for Critical Infrastructure Protection) (http://www.ccip.govt.nz) provide regular bulletins for the NZ environment.