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From: James Carlson <>
Subject: Re: IPv6 with pppd
Date: Wed, 26 Jun 2019 12:45:43 +0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 06/26/19 07:30, Levente wrote:
> Dear maintainer,
> I am struggling with IPv6 over PPP on Linux. The situation is that I
> have a 3G modem, when I plug it in to the USB on my Debian box,
> everything works as expected, I have IPv6 address from the provider,
> and I am happy. But how?

There may be problems with this trace, possibly indicating 3G-specific
authentication issues, but if your only question is about IPv6, the
answer is very simple.  PPP doesn't negotiate global scope addresses in
IPv6.  It does link-local only.  Global scope addresses come from either
ICMPv6 Router Advertisements, DHCPV6 address assignments, or static

> Please note that in the logs, I can't see that global scope address,
> and I don't know how the IPv6CP assigns this address to the interface.
> How is this done?

Some other protocol.  IPV6CP is not involved.

> And when I plug the same modem to an OpenWRT box, I don't get the
> global scope address, only the link-local address. Is this some PPP
> specific problem, or there might be some IPv6 autoconfiguration magic
> happening in the background? I don't think so, because that address
> corresponds to a statically allocated address of the provider.
> lev@mercury:~$ host 2a00:1110:135:4594:303e:582f:ea95:aa10
> domain name pointer
> Could you help me out what is going on here, and why can't I get a
> global scope address on the OpenWRT? I'm sure it is an OpenWRT issue,
> but need help tracing it.

My guess would be that the OpenWRT box doesn't have IPv6 routing enabled
and isn't doing RAs.  That's just a guess.  I don't believe the issues
you're having here have anything to do with PPP.

James Carlson         42.703N 71.076W         <>

  reply	other threads:[~2019-06-26 12:45 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-26 11:30 Levente
2019-06-26 12:45 ` James Carlson [this message]
2019-06-26 14:43 ` Levente
2019-06-26 15:28 ` Michael Richardson

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