IPv6 Troubleshooting for Helpdesks
Contents
1. Network problem If your organization dynamically assigns IP addresses then escalate If your organization statically assigns IP addresses verify that the customer has the proper details per company documentation for WAN LAN and default gateway If the customer confirms that the details are entered as assigned then escalate check the router A future version of this document will offer more ULA advice as we gain more experience 6to4 disable 6to4 using http support microsoft com kb 929852 for example Microsoft Fix it 50412 Teredo disable using http support microsoft com kb 929852 for example Microsoft Fix it 50412 This address is a known invalid address Encourage the customer to call their router vendor for support Any other single address Multiple addresses At least one matches our address Multiple addresses If none match our address but at least one address starts with 2001 0 or 2002 Still here Either the host is manually misconfigured or another device on the customer s network is offering broken IPv6 services and possibly misconfigured They will need to possibly seek on site help Host selection problem Network problem Windows Disable tunnel interfaces using http support microsoft com kb 929852 for example Microsoft Fix it 50412 If only one address remains test with test ipv6 com and consult this table if problem2. IPv4 Good AS65536 CableCo IPv6 Good AS65536 CableCo OtherSites 40 40 good IPv4 address 192 0 2 1 IPv6 address 2001 db8 1 Interpretation IPv6 is working great IPv4 works only with named connections and web sites Connections by raw IPv4 address fail This is probably not an error condition but is explicitly called out in case of support issues with specific IPv4 applications Action Typically none If you need IPv4 to work and your organization has depoyed 464xlat you may need to ensure that your customer has properly configured their device for your 464xlat service With a working 464xat your customer should instead see a help desk code of 46 IPv4 IPv6 64t NAT64 possible tunnel Example results 10 Help desk code 64t NAT64 possible tunnel IPv4 Good AS65536 CableCo IPv6 Good AS64511 AnotherCo OtherSites 40 40 good IPv4 address 192 0 2 1 IPv6 address 2001 db8 1 Interpretation IPv6 is working great IPv4 works only with named connections and web sites Connections by raw IPv4 address fail This is probably not an error condition but is explicitly called out in case of support issues with specific IPv4 applications Action Typically none If you need IPv4 to work and your organization has depoyed 464xlat you may need to ensure that your customer has properly configured their device for your 464xlat service With a working 464xat your customer should instead see a hel
3. reached using Teredo instead of native IPv4 Modern operating systems do not prefer these kinds of tunnels by default Be aware that the user might have a very old operating system or a non default configuration Action Have the user disable any automatic tunneling mechanisms that are active Teredo is a protocol that runs on the PC and tries to get IPv6 traffic through a NAT device or firewall Disable tunnel interfaces using http support microsoft com kb 929852 for example Microsoft Fix it 50412 46 IPv4 IPv6 Example results Help desk code 46 IPv4 IPv6 IPv4 Good AS65536 CableCo IPv6 Good AS65536 CableCo OtherSites 40 40 good IPv4 address 192 0 2 1 IPv6 address 2001 db8 1 Interpretation This is an example of a healthy IPv4 IPv6 configuration Both IPv4 and IPv6 are working at least to this web site Action None unless the OtherSites test reports any problems If problems are reported investigate possible IPv6 routing or peering issues If the company had a dual stack speed test server try that to identify performance issues 46t Dual Stack Possible Tunnel Example results Help desk code 46t IPv4 IPv6 IPv4 Good AS65536 CableCo IPv6 Good AS64511 AnotherCo OtherSites 40 40 good IPv4 address 192 0 2 1 IPv6 address 2001 db8 1 Interpretation This is an example of a healthy IPv4 IPv6 configuration The IPv6 connectivity appears to be announced by a different en
4. 6 WAN provisioning often requires a router modem reboot 4 IPv4 only Example results Help desk code 4 IPv4 only IPv4 Good AS65536 CableCo IPv4 address 192 0 2 1 Interpretation User s issue is not caused by IPv6 as there is no IPv6 configured If Teredo was found and mentioned we determined it is safe and not actively being used for connections to web sites by DNS name Action 1 Determine whether IPv6 is available in this area based on company documentation 2 Confirm whether the user s equipment modem router support IPv6 based on company list of approved devices Some retail equipment may also support IPv6 A firmware upgrade may be required a reboot may trigger a firmware upgrade or your company may have documented processes to upgrade firmware 3 If the company has processes to configure IPv6 manually do so and test again Most residential ISPs automatically configure IPv6 where available so manual configuration is not possible 4 Configure IPv6 on the user s device using vendor documentation At IPv4 plus Teredo Example results Help desk code 4t IPv4 plus Teredo IPv4 Good AS65536 CableCo IPv6 Good Teredo Preferred OtherSites 40 40 good IPv4 address 192 0 2 1 IPv6 address 2001 db8 1 Interpretation Teredo was used to provide an IPv6 address and the host was configured to actively take advantage of this service Any web site that has an IPv6 presence will be
5. IPv6 Troubleshooting for Helpdesks Using test ipv6 com Draft v 00 Contributors and authors Lee Howard John Jason Brzozowski David Freedman Jason Fesler Tim Chown Sander Steffann Chris Grundemann Jan Zorz 1 What is a BCOP 2 Summary Appeal 3 Background History 4 Using This Document Note for Helpdesk Managers 5 IPv6 Troubleshooting 112 IPv4 plus Broken IPv6 4 IPv4 only 4t IPv4 plus Teredo 46 IPv4 IPv6 46t Dual Stack Possible Tunnel 624 6to4 64 NAT64 64t NAT64 possible tunnel slow mtu Possible MTU issues Warning Site s with failed connectivity Warning 6 IPv6 training for helpdesk 7 Conclusion 8 Operator s specifics 1 What is a BCOP A current document describing how to best achieve an operational practice agreed by subject matter experts and periodically reviewed by community 2 Summary Appeal This BCOP provides a basic and generic foundation for any user centric helpdesk that deals with IPv6 customer connectivity The focus is on techniques and solutions for the most common IPv6 user connectivity issues While these issues are often found in residential ISP networks enterprise IT helpdesks and other front line support personnel should be well served by this BCOP 3 Background History Many network operators who deal directly with end users are concerned about deploying IPv6 One complaint often sounds something like We deployed IPv6 in our netw
6. ed IPv6 troubleshooting Educate yourself and your helpdesk team on IPv6 Feedback on this document should be sent to Jan Zorz at zorz isoc org 8 Operator s specifics What your helpdesk should also know and is specific to your company operator 14
7. er is using a tunnel suggest they change their tunnel to a closer location mtu Possible MTU issues Warning Example results Help desk code 46 IPv4 IPv6 IPv4 SLOW AS1234 CableCo IPv6 SLOW AS1234 CableCo WARNING POSSIBLE MTU ISSUE in RED OtherSites 40 40 good 12 IPv4 address 192 0 2 1 IPv6 address 2001 db8 1 Interpretation IPv6 MTU issues are typically caused by ICMPv 6 filtering at some point along the path Small requests were fast large requests were slow and or timed out There are too many possible solutions to be checked Action This issue requires deeper understanding of IPv6 protocol and solving of this issue depends on how your helpdesk is organized If you have two or three tier helpdesk hand it over to second level support with clearly noting that there are MTU issues If you have just one tier helpdesk hand it over to appropriate escalation department contact depending on your escalation policy Action MTU issues are most often caused when Path MTU Discovery PMTUd RFC1981 fails Check firewall configuration on user s CPE look for the blocking of ICMPv 6 specifically type 2 either explicitly configured or implicitly established through lack of rules permitting this Check for ICMPv 6 filtering on the user s path through your access and core network Follow your escalation procedure when needed Educate your self and your helpdesk team on IPv6 There a
8. ion Also the technician may need to determine whether IPv6 address space is allocated from the company supply the technician with a list of valid prefixes used Based on the helpdesk structure the instruction to escalate may occur at different times 5 IPv6 Troubleshooting Most connectivity problems are NOT IPv6 related at all Calls related to IPv6 are very rare Have user visit http isp test ipv6 com If the user cannot reach the site at all follow standard procedures and scripts to determine whether there s a physical connectivity problem or other standard complication If the site is available to the user continue using this document If IPv4 is working but the page is unavailable check DNS In the user s device s network settings check DNS name servers If the servers there have IPv6 addresses check connectivity to those servers e Windows Open a cmd window and run ping address e MacOS Open a terminal window and run ping6 address If they are not reachable configure different servers isp test ipv6 com reports test results in a very compact way Help desk code xx Summary Status of IPv4 slow timeout warnings ASN and ISP name Status of IPv6 slow timeout warnings ASN and ISP name Major warnings such as MTU Status of reachability to other sites IPv4 address IPv6 address Ask the user to read the help desk code near the top in Blue Then find that code in blue below t
9. n the application In the command prompt window type ipconfig and press enter When done reviewing the data type exit and press enter a Windows 7 Windows Vista Click the Start button Type cmd to search for the command prompt Click cmd exe to open the application In the command prompt window type ipconfig and press enter When done reviewing the data type exit and press enter a Windows XP Click the Start button Click the run option Type cmd and hit enter In the command prompt window type ipconfig all and press enter When done reviewing the data type exit and press enter m Apple OS X from https kb wisc edu helpdesk page php id 9257 e Open Terminal o Click the Spotlight search icon in the upper right corner o Type Terminal o Click the Terminal icon from the search results Type ifconfig grep inet6 to get the list of IPv6 addresses When done either type exit or click the red button on the terminal window 4 Check the IPv6 addresses Ignore the addresses that start with fe80 or 2001 0 and address 1 Identify any remaining address es and use the following table All addresses start with SP allocated IPV6 space All addresses start with fc or fd All addresses start with 2002 All addresses start with 2001 0 One or more addresses start with 2001 db8 or 2005 123 456 789
10. o identify the problem and troubleshoot it The list of help desk codes follow from http test ipv6 com faq_helpdesk html 112 4 At 46 46t 624 64 64t IPv4 plus Broken IPv6 IPv4 only IPv4 plus Teredo IPv4 IPv6 Dual Stack Possible Tunnel 6to4 NAT64 NAT64 Possible Tunnel IPv6 only 112 IPv4 plus Broken IPv6 Help desk code 112 IPv4 plus Broken IPv6 IPv4 Good AS65536 CableCo IPv6 broken IPv4 address 192 0 2 1 Interpretation IPv6 network connectivity somewhere between the user and the website is broken IPv6 connections are timing out instead of succeeding or failing fast to IPv4 The user experience visiting major web sites may be suffering and some applications completely failing Assumption User has already power cycled home router modem and device as part of your standard troubleshooting procedure Action 1 Determine whether IPv6 is offered to this customer based on company documentation 2 Confirm whether the user s equipment modem router supports IPv6 based on company list of approved devices Some retail equipment may also support IPv6 A firmware upgrade may be required a reboot may trigger a firmware upgrade or your company may have documented processes to upgrade firmware 3 Identify the customer s IP address m Windows 8 1 Press windows key to go to the Start Screen Type cmd to search for the command prompt Click Command Prompt to ope
11. ork and all our services but will not roll it out to our residential customers because our helpdesk knows nothing about it and we can t do it The issue would be solved in many cases if the operations folk would have a very simple and generic document template where the lowest common denominator of procedures and troubleshooting tips would be documented so they would just add their specifics and hand over to helpdesk manager saying Hey we implemented IPv6 and here are a few basic things that your people need to understand and know While this document cannot encompass all possible problems it should provide a solid first step for front line support personnel 4 Using This Document Note for Helpdesk Managers This document is intended as a template that can be altered and supplemented with all individual company specifics needed so each company builds the most suitable policy and procedures to follow when the IPv6 issue is detected This document relies heavily on the site http isp test ipv6 com written by Jason Fesler in support of this document ISPs should strongly consider running a local mirror so they can provide their own support In those cases replace the text isp test ipv6 com with test ipv6 example net isp or whatever your site is called Several cases rely on checking setting on the home router The helpdesk technican will need to be familiar with the router configuration or refer to vendor documentat
12. p desk code of 46 IPv4 IPv6 Interpretation 2 The IPv6 connectivity appears to be announced by a different entity or at least a different BGP ASN than IPv4 Action Ask the user to read the IPv4 and IPv6 lines ensure that the ASN or company name represented makes sense for your organization If the user is using a foreign IPv6 service consider reprovisioning the user to your own IPv6 service 6 IPv6 only Example results Help desk code 6 IPv6 only IPv4 no IPv6 Good AS65536 CableCo IPv6 address 2001 db8 1 Interpretation Only IPv6 found 11 Action Refer to the IPv4 helpdesk IPv6 is working perfectly Note IPv6 only users do not trigger the OtherSites check Without IPv4 there is no way to know whether to report an IPv6 reachability problem or to ignore it due to site down Note IPv6 only users will need to use http ipv6 test ipv6 com helpdesk or http ipv6 test ipv6 com isp slow Example results Help desk code 46 slow IPv4 IPv6 slow IPv4 SLOW AS1234 CableCo IPv6 SLOW AS1234 CableCo OtherSites 40 40 good IPv4 address 192 0 2 1 IPv6 address 2001 db8 1 Interpretation IPv4 or IPv6 connections for very short requests to the test ipv6 com site took over 5 seconds Action Follow standard procedures and scripts to determine whether there s a physical connectivity problem or other standard complication If only IPv6 is slow if the us
13. re several outstanding resources available to folks new to IPv6 Internet Society Deploy360 http www internetsociety org deploy360 ipv6 http www networkworld com community blog mtu size issues http en wikipedia org wiki Maximum_transmission_unit Site s with failed connectivity Warning Example results Help desk code 46 IPv4 IPv6 IPv4 Good AS1234 CableCo IPv6 Good AS1234 CableCo OtherSites 39 40 good 1 40 bad IPv4 address 192 0 2 1 IPv6 address 2001 db8 1 Site s with failed connectivity in RED test ipv6 example com http ipv6 test ipv6 example com images nc knob_valid_green png 13 Interpretation One or more sites are unreachable by the user only when using IPv6 Action Ensure the user is using your network services If this error condition perists or can be confirmed engage your network routing team to look into it 6 IPv6 training for helpdesk IPv6 training for helpdesks is available from many IPv6 training companies all around the world or can be tailored to suit the needs from their basic IPv6 training for engineers and technical staff When you are rolling out IPv6 in production you need to train all your staff to equalize the IPv4 and IPv6 knowledge anyway so talk to your training agency and ask them to adapt their IPv6 education program and train your helpdesk team 7 Conclusion Most connectivity problems are NOT IPv6 related at all Use http isp test ipv6 com for automat
14. s persist If there is a home router first determine if IPv6 is configured on the WAN if it is not there 3 should be no IPv6 configured on the LAN a Check the configuration of the home router if an IPv6 address is visible on the WAN port e g 2001 db8 1234 abcd 83 64 but not on the LAN port troubleshoot with vendor documentation b Check the LAN settings on the home router refer to vendor documentation If it has not given out any IPv6 addresses troubleshoot with vendor documentation If the home router has a working WAN connection make sure that the automatic provisioning on the LAN is correct Ensure that an appropriate IPv6 prefix was delegated to the home router and assigned to LAN interface s a Check the configuration of the device papo Check the configuration of Router Advertisements on the home router Check the configuration of the DHCPv6 server on the home router Check the device for the proper provisioned prefix Check the device for a matching set of LAN prefix es If the home router is providing the correct information to the LAN check if the user device is overriding those settings a Check if the user device has static address settings that don t correspond to the settings on the home router 5 Have the user re run the ISP Test IPv6 test and provide new results a If not fixed start the troubleshooting process again b Follow your escalation procedure when needed Note Enabling IPv
15. tity or at least a different BGP ASN than IPv4 Action Ask the user to read the IPv4 and IPv6 lines ensure that the ASN or company name represented makes sense for your organization If the user is using a foreign IPv6 service consider reprovisioning the user to your own IPv6 service 624 6to4 Example results Help desk code 624 6to4 IPv4 Good AS65536 CableCo IPv6 Good 6to4 Preferred IPv4 address 192 0 2 1 IPv6 address 2001 db8 1 Interpretation 6to4 was used to provide an IPv6 address and the host was configured to actively take advantage of this service Any web site that has an IPv6 presence will be reached using 6to4 instead of native IPv4 Modern operating systems do not prefer these kinds of tunnels by default Be aware that the user might have a very old operating system or a non default configuration Action Have the user disable any automatic tunneling mechanisms that are active 6to4 is a protocol that runs on the PC and tries to get IPv6 traffic through a public relay using IPv4 as a temporary transport device Public 6to4 relays offer no SLA and published studies show approximately 15 failure rates Windows Disable tunnel interfaces using http support microsoft com kb 929852 for example Microsoft Fix it 50412 If IPv6 is desired configure IPv6 and test again Verify the user has an IPv6 address and a default route 64 NAT64 Example results Help desk code 64 NAT64
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