Questions tagged [ipv6]

For questions about Internet Protocol version 6 (IPv6); as specified in RFC 8200.

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2
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1answer
318 views

Why is only 24 bits of the MAC address used for multicasting?

When doing neighbor discovery in IPv6, the last 24 bits of the hosts MAC address is glued on to some link local multicast prefix. I'm wondering why 24 bits? Why not 48, or 32, or 16? What happens if ...
2
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1answer
83 views

Mobile Node home address and Mobile Node Home Agent Address

I have been reading mobile IPv6 for a while and in that the two terms: Mobile Node's Home address and Mobile Node's Home agent address are used frequently, and they seem similar to me. My ...
2
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1answer
66 views

The length of Fragment header in IPv6

From RFC2460 :https://tools.ietf.org/html/rfc2460#section-4.5, the length of the fragment header seems to be fixed 8 bytes. But when I test with Scapy with the default fragment header, from sniffer ...
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5answers
266 views

Since we ran out of IPv4 now, what does it mean for consumers?

I'm trying to understand what it means for users... Does it mean that some content will not load on websites, increasingly so in the upcoming year or so? Does it mean that certain CDNs or hostings ...
2
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1answer
83 views

Parse the Encapsulating Security Payload

RFC2460 defines some extension headers, like hop-by-hop, Routing Options...etc. All these headers seem to have the next header type and header extension length in the beginning of the header. However ...
7
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1answer
4k views

Smallest IPv6 block advertised?

We've received a /48 allocation from ARIN, and want to advertise smaller blocks from different sites in our organization. I tried advertising a /56 from each site, but ISP is telling me they won't ...
1
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0answers
59 views

IPv6 network addresses with 6to4 router and tunnel [closed]

I'm currently studying for an upcomming exam and I came across the following question, the IP-Addresses are to be filled in by me and this is my try at solving it, but I'm not sure if the IP-Address, ...
1
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1answer
58 views

Design thinking of Solicitation node address in IPv6

Recently I study RFC 4291, and the solicitation node address is defined in that spec. I know what and the function of this solicitation node address. But just wondering why does the address design as ...
0
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1answer
45 views

Can there be any extension header before Neighbor Solicitation Payload

The IPv6 payload may like the following: IPv6 Header -> ExtHeader -> ... -> UpperLayer Header I use Scapy to make a packet such that: IPv6 -> Hop-by-Hop-Option -> Neighbor Solicitation [1] However ...
7
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2answers
47k views

Stateful vs Stateless IPv6?

What's the difference here? Are stateful IPv6 entries retained in the DHCPv6 server?
1
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2answers
257 views

How will ISP's handle the future of IPv6 to pro-sumers [closed]

With IPv4, ISP's rarely, if ever, assigned a static IP to a consumer except for maybe AT&T and a few local carriers unless you registered as a business account with them. I understand with the ...
4
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1answer
761 views

Why do some AAAA records behave strangely on existing A records?

I noticed the following odd behavior with AAAA records when querying existing A records. By base domains I mean domain names without subdomains. So when an A record exist and an AAAA record does not ...
1
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3answers
610 views

Is it ok if multiple non-router devices send IPv6 RAs with same prefix in the same network?

We engineer embedded systems (electronics & software), running our own OS with LWIP (a network stack). The device is configured to be IPv6 only (means: no IPv4 is available). These embedded ...
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0answers
208 views

Subnet delegated prefix on SRX

I configured a Juniper SRX firewall to receive IPv6 prefix from upstream router: family inet6 { dhcpv6-client { client-type statefull; client-ia-...
2
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1answer
429 views

Do different nodes on a LAN share a public IPv6 address?

I looked up the public IPv6 addresses on google for two devices on my LAN, and the addresses are unique (only the first 64 bits match). I thought that the router connected to the internet has a ...
2
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1answer
74 views

IPsec tunnel with IPv6 and security gateways

Silvia Hagen wrote in one of her books (ISBN:9783952294222, page 463) the following (free translation from german): Tunneling, an essential element of IPsec [...], is problematic for existing ...
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3answers
221 views

Can you keep DHCP addresses from your ISP

I have my modem configured for bridge mode. I get one IPv4 for my router and one goes to my server for public access. If I static assigned these IPv4 address would I keep them as long as no one else ...
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3answers
2k views

How is NAT a hack?

Forgive me if this sounds a little amateurish, or if this is the wrong stackexchange, but...most of my entirely life I've had ipv4 behind a NAT router. I've been told that this was a hack; simply ...
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0answers
352 views

DHCPv6 - When is the Status Code Option added to the options field of an IA Address Option?

I was wondering if someone would be able to tell me when is the status code option (OPTION_STATUS_CODE) added to the options field of a OPTION_IAADDR or OPTION_IAPREFIX (RFC3633). The RFC seems to ...
4
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0answers
410 views

IPv6 link-local addresses for virtual interfaces are identical - how to assign “link-unique”? [closed]

I have a VPN connecting two virtual interfaces of two hosts. Both VPN interfaces have MAC addresses 00:00:00:00:00:00, as the OS (Linux) assigns link-local IPv6 address based on MAC address. So the ...
1
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1answer
139 views

Will an asa pass traffic that matches a crypto map entry if Phase 2 is not completed?

I have two ASAs that have publicly routable ipv6 addresses, and a /56 at each site. Since we're going to be rolling out ipv6 internally at some point for all users, I'd really like to prevent packets ...
2
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1answer
757 views

Will home networks migrate to ipv6? [closed]

So I have a rudimentary understanding of working with basic networking tools, things like using nmap to scan ports and find IP addresses on internal networks, and ssh for connecting to various devices....
3
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1answer
970 views

How to calculate the Subnet address?

I have an ipv6 address FC00::50, and the subnet mask length is 64. How to calculate an subnet address? I want address FC00::50 in the scope of this calculated subnet address. Here is the description: ...
5
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2answers
11k views

How to understand the IPv6 route table [closed]

Here is the ip -6 route result of my working OpenWRT system. I find that this is quite different to the route table of ipv4. default from :: via fe80::3e8a:b0ff:fe86:f870 dev eth0.2 proto ...
2
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1answer
680 views

IPv6 Testing Addressing Type Confusions

I'm new in the IPv6 Topic and Yesterday I was performing some testing on Cisco IOS and Cisco Routers of the addressing type in IPv6 with RIPng, i was testing the following: Global Unicast Address ...
8
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1answer
765 views

Cisco IPv6 BNG Radius Attributes

I am trying to push out IPv6 unnumbered to an interface via radius. I am trying to do it in a similar fashion to how you would for IPv4: Cisco-AVPair += "ip:vrf-id=vrf-name", Cisco-AVPair += "ip:ip-...
5
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0answers
799 views

Juniper SRX IPv6-PD update-router-advertisement issues

I'm trying to get some sweet prefix delegation working on my SRX. My provider offers DHCPv6-PD and gives out /56 addresses. I have done setups using cisco routers and am trying to replicate it onto a ...
1
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1answer
767 views

IPV6 Client Device not sending Router Solicitation upon expiry of Router lifetime [closed]

we have a test case from the operator that upon expiry of router lifetime the client device supposed to send Router solicitation message to the router. But this is not happening. is this because of ...
2
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0answers
662 views

IPv6 Neighbor Discovery procedure with a ping example [closed]

Given the following capture (click to zoom): There are 3 routers attached to a switch. One of them pings FF02::1 (packet #2). I understand, that the other two routers have to figure out the first ...
5
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2answers
349 views

Will a default-deny rule on incoming connections of an IPv6 firewall negate any advantages that were gained by not having NAT?

Will a default-deny rule on incoming connections of an IPv6 firewall negate any advantages that were gained by not having NAT? In other words, one of the most talked about advantages to IPv6 is that ...
1
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1answer
709 views

router advertisement packet

Networking beginner here, trying to understand the output of the tcpdump tool using a captured router advertisement packet. tcpdump -i wlp4s0 -nn -t -c1 -vvv -X -s0 Based on what I've found online, ...
2
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2answers
949 views

Man In The Middle on IPv6, are IPv4 packets affected?

If I successfully Man in the Middle attack an IPv6 Address of my victim can I also sniff its IPv4 packets? Attacks like Neighbor Advertisement Spoofing or Last Hop Router?
3
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1answer
1k views

What is the advantage of multicasting in IPv6 (compared to broadcast)?

I've been trying to familiarize myself with IPv6 and one thing that's left me hanging is the benefit of multicasting over broadcasting in IPv6. To use Neighbor Discovery Address Resolution as an ...
2
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1answer
3k views

can pfsense perform ipv6 nat (for outbound service redirection)

I have to keep prefacing my question with "I am not trying to reimplement ipv4 nat inbound for outdated security I don't understand correctly". Hi! I am wondering if it is possible to implement an ...
1
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1answer
101 views

ICMPv6 RA to make it as default gateway in the Network

Hey guys if you are familiar with ICMPv6, i have a problem right now considering RA. I am trying to come up with a mitigation for last hop router attack, so i thought of how about sending a packet ...
1
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1answer
191 views

IPV6 Neighbor Advertisement (NA) not recieved

I'm trying to make a project to detect NAs in an inter-vlan IPv6 environment via trunk line. I know that NAs are sent in multicast so it would be possible to see the NA messages using a trunk line. ...
1
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1answer
225 views

Question about Duplicate Address Detection with VLANS?

Consider the case of a Router-on-a-Stick topology with multiple vlan tags, when a new computer joins the network. Will the DAD Neighbor Solicitation message be tagged with a VLAN? Will all the ...
4
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2answers
116 views

IPv6 addresses allocation

I need to allocate IPv6 /48 block from one provider to another, located in different country. Is it possible at all? I don't own this block but let's assume that current provider will agree to "...
0
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1answer
2k views

May every IPv6 address be written as an IPv4-mapped IPv6-address?

In RFC 5952 - section 5 it is stated that for some IPv6 addresses it is recommended to give the mixed notation, if it has a certain prefix. However, it is unclear which prefixes are used for this, ...
2
votes
1answer
942 views

Generate list of IPv6 subnets on router using SNMP?

As a follow-up to Generate list of subnets on switch using SNMP?, we would like to do the same thing for IPv6 - i.e. poll all of our routers (Juniper and Cisco, at least for now) to identify which ...
13
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4answers
9k views

Why is the U/L bit inversed in EUI64?

This inversion is bijective, so I can't figure out what is it's use.
5
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1answer
1k views

Cisco 6rd configuration example - ipv6 general-prefix

I'm currently learning the IPv6 tunneling via IPv4 in GNS3. I've done manual tunnels, 6to4 and now I'm tackling 6rd. I've read on the subject and I think I get the whole concept..The IPv6 prefix, the ...
3
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2answers
231 views

Neighbor Discovery Protocol

When IPv6 is performing NDP and the message is Neighbor Solicitation and the observation point is between two routers, what would the IPv6 source address be? The one from the host or the one from the ...
4
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1answer
155 views

Cisco IOS: OSPFv3 route cost

Cisco IOS 12.4T and later: show ip ospf rib informs about the cost for each network learned by OSPFv2. What command does the equivalent for OSPFv3?
3
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2answers
467 views

How to solve this IPv6 looping problem?

I have set up a 6in4 tunnel, namely "sit1", but I have discovered that if I traceroute non exist IP within the subnet, it will loop. What should I do to solve this? The routing table:
7
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1answer
1k views

MLD messages during IPv6 duplicate address detection

I was wondering if anyone can shed some light on when Multicast Listener Discovery (MLD) messages ought to be send during IPv6 Duplicate Address Detection. RFC4862 section 5.4.2 gives a detailed ...
3
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3answers
347 views

Which private IP addresses can be used internally?

Does IPv6 have a private IP addressing scheme?
3
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2answers
862 views

EX4200 / EX3300 IPv6 Routing Question

we have about 5 Servers and currently only a cheap L2 Switch. We got an /42 IPv6 Network assigned from our provider and want to route this /42 Network into multiple /64 subnets. These can just be ...
4
votes
4answers
8k views

Why there are no different classes of network in IPv6?

In IPv4 we have class A, class B, and class C. In IPv6 we have only global prefix and Interface ID. I know there are plenty of addresses in IPv6 but it gives room for too many host addresses.And when ...
6
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2answers
2k views

IPv6 Multicast - Purposes for the Interface-Local scope?

On an IPv6 multicast packet, the last nibble of the first hextet represents the Scope of the packet. This defines effectively how far you want your multicast packet to travel. The address makeup is ...

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