Questions tagged [ipv6]

For questions about Internet Protocol version 6 (IPv6); as specified in RFC2460.

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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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1answer
80 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 ...
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1answer
77 views

Are there ways on knowing/predecting how long/many are the delay/attempts of Duplicate Address Detection?

Hi guys need help on my project, I was stuck on this research where I am looking for knowing how long is a usual DAD. I'm looking thru the RFC and what I got is that it has a "Random Delay" but ...
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1answer
1k views

IPv6: to VRF or not to VRF

Been discussing this with people and reading up, would like people's thoughts on whether or not its worth running IPv6 in a VRF or just let it loose in the global routing table. Even though ...
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1answer
65 views

Confusion about IANA “Protocol Numbers” registery

In the IANA registery for "Protocol Numbers", there listed 2 IP protocol versions: IPv4 at #4 and IPv6 at #41. Their "protocol" column says IPv[46] Encapsulation, and "reference" column points to 2 ...
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1answer
62 views

configure IPv6 ACL on interface WS-C3750X-48

I am using  WS-C3750X-48 model switch. license is lanbase. I have activated cmd on my switch: sdm prefer dual-ipv4-and-ipv6 routing. Then i did reload. After that, i will able to config IPv6 on ...
2
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1answer
173 views

Setting Destination MAC address for RTP/UDP packets

I have a requirement where I have to send the UDP packet to a destination multicast IPv6 address. In addition to that the packets must also have corresponding destination multicast MAC address set. I ...
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2answers
5k views

pfSense IPv6 NAT

I know many of you said that IPv6 has no NAT, but my server provider told me, that it is possible. I have no idea how... I have a pfSense Server as my Firewall (Not the router!). I have a /28 IPv4 ...
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1answer
285 views

assigning ULA and global adresses simultaneously

For my internal Network, i'd like to set up IPv6 with ULAs assigned with DHCPv6, a bit like with IPv4s RFC1918 private addresses: I'm independent from the Prefix of my ISP for the internal networking ...
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1answer
556 views

IPv6 ULA vs. Global addresses for private (intra entity) peering

I am working on converting my core to IPv6. My current addressing scheme includes the VLAN in the IPv6 address: VLAN1511: XXXX:XXXX:XXXX:1511::1/64 However I have some VLAN overlap (the same VLAN ...
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1answer
171 views

Difference in convergence time IPv4 vs IPv6

Using protocols like RIP, OSPF and EIGRP, would IPv6 converge faster in smaller network like 4 routers? Would it differ in bigger networks?
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138 views

Is the structure of the CEF IPv6 trie similar with the IPv4 trie structure?

Is the structure of IPv6 mtree similar with the IPv4 mtree structure? Have you guys seen any documentation about this subject?
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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 ...
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1answer
427 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 ...
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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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0answers
51 views

RPL: questions on routing mechanism

I'm studying RPL and two questions came to my mind: 1: Both in storing and non-storing modes, if a node wants to send a packet to another node via P2P communication paradigm, then how does the ...
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57 views

DHCP ivp6 vs DHCP ipv4 router config (cisco) [closed]

When setting up a router as dchp server in ipv4, we specify a pool under which we give the network and the default-gateway and that's it: However in ipv6 stateless dhcp , we create the pool then ...
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164 views

How is the source link-layer address in IPv6 router solicitation(RS) messages used?

When I analyze the router solicitation(RS) messages, then they contain the MAC address of the sending host. How does the router use this MAC address seen in ICMPv6 message? Does it simply use it as a ...
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0answers
650 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 ...
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5answers
1k views

IPv6 address assigned to vlan interface of 3750 switch changes

When setting up my 3750 stacks, I enable IPv6 on the Vlan1 interface so that I can manage the stack over IPv6. The stacks are not doing any layer 3 routing. However, it seems that the IPv6 address ...
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1answer
2k views

Why is IPv6 expressed in hexadecimal format?

Why is ipv6 hex? Is it still okay to express it in denary? sure xxx.xxx.xxx.xxx.xxx is easier to remember than AAAA AAAA AAAA AAAA AAAA AAAA ?
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2answers
805 views

OSPFv3 - Sample configuration (Dual Stack IPv4 and IPv6) - Cheat Sheet

When configuring OSPFv2 on a router, you type in router ospf 10 router-id 1.1.1.1 network 10.0.0.0 0.0.0.3 area 0 for example. That way the network can be advertised per LSAs. But in OSPFv3 it ...
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2answers
229 views

Why subnetting is implemented if we can use Network Address Translation (NAT)

As in subnetting a block of IP adresses are allocated, which leads to consumption of those IP addresses. Then how come we don't use Network Address Translation (NAT) as it will only need one IP ...
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2answers
705 views

Subnet and routing on IPv6

I would like to know: 1) What is the smallest routable subnet size in IPv6 ? 2) Can a /128 address be routed in a IPv6 network?
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1answer
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Next Header field in IPv6 vs Protocol field in IPv4, any difference?

So I am new to the IPv6 concept, and I seen that the Protocol field seems to be replaced with Next Header, and I have a question. Question: Is Next Header a complete replace of Protocol, or is they ...
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2answers
69 views

Why is the IPv6 link-local address not /9?

According to this answer, it's because computers read addresses in binary. Fine. That explains why the fe80 address does not need to be /12 or /16--it's because everything after the 10th bit is a ...
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3answers
607 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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4answers
72 views

Why not put unicast address in IPv6 packet containing NDP neighbor solicitation instead of solicited-node multicast address?

This is a follow-up question to Why is the NDP Neighbor Solicitation message sent to the solicited-node address?. Summary: say I would send an IPv6 packet and put the unicast address of the host I ...
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1answer
50 views

How can know the subnet mask in IPv6 network?

How the host can know the subnet mask in the IPv6 network, in case the network does not use the default subnet mask which is /64. for example the subnet mask of the network is /88, How can the IPv6 ...
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2answers
99 views

Is it possible to see a Teredo IPv6 address in IPv6 neighbor cache?

Is it possible to see a Teredo address (from 2001::/32 block) in an IPv6 neighbor cache? For example, in the case of Junos, in the output of show ipv6 neighbors. As much as I tested, this is not ...
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2answers
2k views

How to check if switch is ipv6 fully compatible

We will move to IPv6 in the next months and I have a lot of switches and routers and I want to discard IPv6 non-compatible or not fully compatible devices. What kind of standar I will need to check ...
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1answer
763 views

What are the key advantages and disadvantages of NDP compared to ARP?

So why they didn't use ARP in IPv6? is there any real benefit of doing this? what are the key advantages and disadvantages of using NDP instead of ARP? (In overall network performance, Security and ...
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4answers
166 views

IS-IS IPv6 over IPv4

In IS-IS the router knows the interfaces addresses of the other routers. So would it be possible to connect two IPv6 areas over an IPv4 area? A router in area A knows that the destination ipv6 ...
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3answers
171 views

How to do subnetting on IPV6 for non nibble boundaries?

As I was reading this article on How to: calculating IPv6 subnets outside the nibble boundary https://blog.apnic.net/2018/08/10/how-to-calculating-ipv6-subnets-outside-the-nibble-boundary/ The author ...
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1answer
94 views

Pinging computer on a different network

I would like to know if it is possible to ping a computer on a different network using ipv6. If I am understanding it correctly then IPV6 was created for each device to have its unique ip address. ...
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3answers
8k views

Access Server ipv6 from a ipv4 only network

One of my Server is sitting behind a network which is only accessible trough a IPV6 (no double stack IPv4/IPV6 available). How can I access the server (SSH, HTTP, other protocols) from an network ...
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1answer
91 views

Which part of an IPv6 address is assigned by the RIR?

Given my PC or any other, which part of the IPv6 address is allocated by the RIR and which part is allocated by the ISP? I know a prefix of /64 is commonly used, does that mean the bits before the /...
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2answers
438 views

Link Local Address using in NDP (IPv6)

How is using of link local address in NDP. We can discover neighbor by using global address. So why we need link local address in NDP?
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2answers
202 views

How does WAN work?

I understand the basics. WAN is a network that connects multiple LANs together. Usually the router is the connection between the LAN and WAN. But I have some questions books and the internet could not ...
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1answer
99 views

Unsecured devices and IPv6

I'm currently starting to read up on IPv6, and as soon as I heared that every device can/will have a public accessible adreess i got a little freaked out. There are a lot of horror stories about ...
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2answers
335 views

IPv6 link local address unicity on a routed network

Going through an exercise from the CCNA practice exam I encountered an example that required the configuration of link local addresses on all interfaces. On Router 1 all interfaces were set to FE80::...
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2answers
372 views

Do NDP and Link Local addresses remove the need for a router to have multiple routable IP addresses?

I'm trying to get my head round IPv6. I've stumbled on something which surprised me, and I'm looking to understand this better in terms of networking: Do Link Local addresses remove the need for a ...
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3answers
129 views

How would I make a client find a server with an unknown IPv6 Address?

Let me first explain my situation: I am currently in the process of trying to build a solution for managing multiple Internet of Things devices on a network. It should be possible to automatically ...
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1answer
141 views

Is Path MTU Protocol more beneficial for IPv6

Should Path MTU Discovery (PMTUD) be implemented over fragmentation regardless of whether it is IPv4 or IPv6? Or should it just be implemented in ipv6 due to fragmentation now being handled through ...
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1answer
65 views

IPv6 address abbreviateion

Given IPv6 address 2001:0000:0000:0000:1111:0000:0000:0000, should it be abbreviated as: 2001::1111:0:0:0 or 2001:0:0:0:1111::? It seems I didn't see any specification talking about it.
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217 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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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 ...
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1answer
702 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, ...
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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 ...
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1answer
260 views

What is the purpose of “Process name” in RIP for IPv6 on Cisco Routers

I was going through Cisco documentation to configure RIP for IPv6. One of the steps says Enables the specified IPv6 RIP routing process on an interface. But they do not go into detail about this ...