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12 votes
Accepted

How does router advertisement in IPv6 avoid IP conflict?

A host performs Duplicate Address Detection (DAD) before actually activating the given address on the interface RFC 2462 has to say about this: 5.4. Duplicate Address Detection Duplicate Address ...
Marc 'netztier' Luethi's user avatar
10 votes
Accepted

Should a router use SLAAC for IPv6 address assignment?

In RFC 7084, it also states: W-1: When the router is attached to the WAN interface link, it MUST act as an IPv6 host for the purposes of stateless [RFC4862] or stateful [RFC3315] interface address ...
Benjamin Dale's user avatar
10 votes
Accepted

dhcpv6 - stateful VS stateless, what is difference between it?

A stateful address assignment involves someone keeping track of the State. Which is to say, some system exists that provides a log that certain IP addresses were assigned to certain MAC addresses. ...
Eddie's user avatar
  • 15k
9 votes
Accepted

Does IPv6 Prefix Delegation work with SLAAC, without the need of a DHCPv6 server/client?

Prefix delegation is a DHCPv6 option. You cannot do it without DHCP. Here is the RFC: https://www.rfc-editor.org/rfc/rfc3633
Sander Steffann's user avatar
7 votes
Accepted

Is possible to use DHCPv6 without SLAAC?

According to RFC4862, Sec 5.5.2 this can happen. However: DHCPv6 does not have an option to provide address of default gateway (explained at the same reference), so in this case default gateway must ...
Effie's user avatar
  • 1,828
7 votes

Should a router use SLAAC for IPv6 address assignment?

RFC 4862 really describes routers within a single administrative control. RFC 7084 clarifies how customer routers should behave. This gives an ISP some freedom in how it supports IPv6 to its customers....
Ron Maupin's user avatar
  • 99.4k
7 votes
Accepted

Method for assigning IPv6 ULA addresses to LAN

After experimenting with this, I have made a few discoveries that end up dictating which path to choose. Multiple subnet advertisements means multiple IPs in the same subnet If you have multiple ...
Malvineous's user avatar
6 votes

Should a router use SLAAC for IPv6 address assignment?

Why does RFC 4862 say "Since host autoconfiguration uses information advertised by routers, routers will need to be configured by some other means." The people who wrote that document (and it's ...
Peter Green's user avatar
  • 13.3k
5 votes

dhcpv6 - stateful VS stateless, what is difference between it?

Stateful configuration Stateless configuration (also known as SLAAC-StateLess AutoConfiguration) The stateful version of DHCPv6 is pretty much the same as for IPv4. Our DHCPv6 server will assign IPv6 ...
Nimesh jani's user avatar
4 votes
Accepted

Do IPv6 addresses have better persistence with DHCPv6?

If you're seeing duplicates with DHCPv4, it's very likely you'd see the same with DHCPv6, because the problem is with your DHCP server and/or configuration. Both systems work exactly the same, ...
Ricky's user avatar
  • 32.1k
4 votes
Accepted

IPv6 Prefix Delegation & propagation through an organisation

Prefix delegation through a site can be performed via DHCP relay chaining; each router in the chain bootstraps the next. The PD should be originated internally to allow you to scope the subnets ...
fileinsert's user avatar
4 votes
Accepted

"ssh: connect to host myserver port 22: Invalid argument" (intermittent, ipv6, link-local address, dhcp hostname)

Whatever is doing hostname resolution is returning link-local IPv6 address(es) that aren't valid for the interface selected -- i.e. "any". Link-local addresses must specify the interface -- eg. fe80:.....
Ricky's user avatar
  • 32.1k
3 votes
Accepted

Can link-local address be used by DHCPv6 Relay

So is there just a configuration I am missing that would allow the Juniper to forward/relay the DHCPv6 from the link-local address assigned to reth0.1 or is it just an absolute must for reth0.1 to ...
Marc 'netztier' Luethi's user avatar
3 votes

ipv6 dhcp pool option link-address

The link-address is the address of the DHCPv6 server on the LAN where the DHCPv6 request came in. It is mostly used with DHCPv6 relays. DHCPv6 messages usually have link-local source and destination ...
Sander Steffann's user avatar
3 votes
Accepted

Two IPv6 global unicast addresses on the same interface (stateless and stateful)

Theoretically, you can assign any number of IPv6 addresses to a single interface. Practically, each OS has a limit, but the limit is far more than two. Each IPv6 interface will normally have a link-...
Ron Maupin's user avatar
  • 99.4k
2 votes
Accepted

assigning ULA and global adresses simultaneously

The basic idea is good. Using both global and ULA addresses in parallel works fine. The only problem you might run into is that not all clients support DHCPv6 (notorious one is Android) so those ...
Sander Steffann's user avatar
2 votes

How Can I configure DHCPv6

You have two options To set up a DHCP relay agent (as stated by Ron Maupin To set a IPv6 pool in your Cisco router DHCP relay agent > enable # config term (config)# interface [interface-1] (...
oxshxll's user avatar
  • 31
2 votes

Why command "ipv6 dhcp relay" doesn't work at packet tracer?

It's an old question - but for anyone finding it you should know that the IPv6 relay agent has not been implemented in Packet Tracer for ANY router.
Jimbugs's user avatar
  • 121
1 vote
Accepted

How is DHCP6 suppose to work with dynamic prefixes?

If your DHCPv6 server cannot learn a dynamic prefix, this is a failing of the software, not the protocol. When the delegated prefix changes, it gets removed. With SLAAC, that's an instant process. ...
Ricky's user avatar
  • 32.1k
1 vote

Can link-local address be used by DHCPv6 Relay

The short answer: You can use a link-local address on the client-facing interface but the DHCP relay must use a routable source address towards the DHCP server and the DHCP relay must provide an ...
Zac67's user avatar
  • 83.9k
1 vote
Accepted

Why command "ipv6 dhcp relay" doesn't work at packet tracer?

The 2811 router is fairly old and End-of-Life since 2016, with the last software updates in 2014 (over four years ago). Your IOS version probably does not support this command. You always need to look ...
Ron Maupin's user avatar
  • 99.4k
1 vote

Stateful DHCPv6 Default Router

My instructor answered my question. Cisco routers will not insert an IPv6 default route into their routing table unless you do a "no ipv6 unicast-routing" command. I tested this in GNS3 and I can now ...
Alex Krycek's user avatar
1 vote

Two IPv6 global unicast addresses on the same interface (stateless and stateful)

Both stateless address autoconfiguration and DHCPv6 may be used simultaneously. But, this means on the same machine, or on the same network? It means on the same machine; more specifically, per-...
Stephen's user avatar
  • 111

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