Re: [v6ops] Subject:,Re: 82nd IETF DRAFT Agenda

["George, Wes" <[e-mail]>]

This long since stopped being about the agenda. Please change the subject line to something more useful to continue the thread about draft-xli-v6ops-ivi-icmp-address

Thanks,

Wes
From: [e-mail] [mailto:[e-mail]] On Behalf Of Ray Hunter
Sent: Monday, October 31, 2011 4:46 AM
To: Joel Jaeggli; Yu Guanghui
Cc: [e-mail] WG
Subject: [v6ops] Subject:,Re: 82nd IETF DRAFT Agenda



Subject:
Re: [v6ops] 82nd IETF DRAFT Agenda

From:
Joel jaeggli <[e-mail]><mailto:[e-mail]>

Date:
Sun, 30 Oct 2011 21:59:23 -0700


To:
Yu Guanghui <[e-mail]><mailto:[e-mail]>

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On 10/30/11 21:53 , Yu Guanghui wrote:



> Here is a example:

>

> ping ivi.dlut.edu.cn   <- it's a pure IPv6 site behind a stateless translator.

> PING ivi.dlut.edu.cn (58.200.163.1) 56(84) bytes of data.

> 64 bytes from 58.200.163.1: icmp_seq=1 ttl=45 time=103 ms

> 64 bytes from 58.200.163.1: icmp_seq=2 ttl=45 time=106 ms

>

> but when we trace it:

>

> traceroute ivi.dlut.edu.cn

> traceroute to ivi.dlut.edu.cn (58.200.163.1), 30 hops max, 40 byte packets

>  1  202.118.66.1 (202.118.66.1)  0.399 ms  0.459 ms  0.582 ms

>  ...

> 10  202.112.61.182 (202.112.61.182)  15.579 ms *  15.503 ms  <- what happened here? maybe a firewall, router or translator?

> 11  * * *

> 12  * * *

> ....

> 29  * * *

> 30  * * *





right...



and we know that  this guy:



202.112.61.182



Is the last hop on this side of the event horizon.  just like if there

were a firewall or a non-stateful icmp filter.







Exactly.

IMHO this case is actually one of the easier cases of ICMP problems to troubleshoot in a modern network, as long as the translator generates an ICMP message with a GUA IPv4 source address.

whois 202.112.61.182

and I get an email address: cernet (dash) helpdesk (dash) ip (at) net (dot) edu (dot) cn

At least you now know who to contact, and they know exactly which box to log into to debug the problem: it's the last hop that isn't showing stars.

And if you find it desirable that the translator should provide additional debug information to end users, that can also be handled out of band e.g. via SNMP, or a web page hosted on the IPv4 address of the translator itself. Many ISP's run such "network looking glass" web servers today already. e.g. lg (dot) he (dot) net.

Try both of those debug solutions with a single specially assigned source address range that is shared among multiple network managers and translators.....

regards,
RayH

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