Questions tagged [ipv6]

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

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1answer
397 views

Any router will automatically join at least two multicast groups on each interface. How do I see that on a Cisco router?

Any router will automatically join at least two multicast groups on each interface. How do I see that on a Cisco router? I know that they all join these two groups: all multicast nodes and all ...
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2answers
728 views

Do we need different VLANs on IPv6 network? [closed]

With IPv6 there's new train of thought around this technology than IPv4. Since this protocol does away with broadcasts, is creating different VLANs necessary? Some people will argue that you can apply ...
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1answer
102 views

IPv6 address scheme for network gear

I'm looking for best practice advice on how to IPv6 address your internal infrastructure network gear (routers, switches, etc). In my searching I've seen some people suggest using /127 like in a /30 ...
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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
1k views

How to split an IPV6 nibble? [closed]

I've been tasked with assigning IPV6 addresses to be split into data centers in several different cities, in several different countries in several different continents. Part of the instructions is to ...
2
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1answer
2k views

Why the FF:FE in EUI-64?

EUI-64 IPv6 addresses are generated from MAC addresses by taking the network prefix (64 bits) and appending the first half of the MAC address, then FF:FE, then the second half of the MAC. Is there a ...
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2answers
533 views

IPv6: is it possible to use a /64 block when you have multiple routers?

I'm new to IPv6 and having some issues with a configuration that was really easy/common with IPv4. My setup looks like this: WAN (ISP managed router) <-> Router 1 ( my internal router ) <-&...
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1answer
39 views

How to know which IPv6 interface will be chosen by the router?

I would like to know how does the kernel decide through which interface it sends data to some IPv6 address, how is the calculation done based on the routing table information: destination, gateway and ...
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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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1answer
129 views

What is rdt_rcv(rcvpkt)/Λ in the given figure?

Please explain. I marked it in a red circle. It's rounded in red color.I got this from the book Computer networking a top down approach.Pg NUM 241. Section 3.4 Rdt 3.0
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1answer
495 views

Basic IPv6 Static Routing (Global Unicast Routing)

I have a topology like this: Every PC and router is configured with IPv6 addresses. -PING from PC1 to R1 is OK -PING from PC2 to R2 is OK -PING from PC3 to R3 is OK -PING from PC4 to R4 is OK ...
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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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5answers
8k views

Why do we need IPv6?

This will be a kind of newbie question but I am not quite sure why we really need IPv6. AFAIK, the story is as follows: In the olden days, when computers were not plentiful, 32 bit IP addresses were ...
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2answers
693 views

Configure tunnel between IPv6 enabled server and local IPv4 network

I am newbie here and also for IPv6 network. I have one debian installed server which is able to send IPv6 traffic. Now in my local network, ISP not supporting IPv6 traffic. I want to configure tunnel ...
2
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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 ...
0
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1answer
49 views

Authentication header doubt

In a book by Forouzan (https://www.amazon.com/Data-Communications-Networking-McGraw-Hill-Forouzan/dp/0072967757) I've read that the sequence number of the authentication header doesn't get repeated ...
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1answer
572 views

IPv4 and IPv6 gateway subnet differences

I understand why for IPv4 the host and the gateway should be part of the same subnet, but for IPv6 I am a little bit confused. There are several types of IPv6 address assignment, but IPv6 requires the ...
5
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2answers
156 views

IPv6 built-in security?

At one time IPv6 was supposed to have built-in security. I don't know how it was supposed to be implemented, but my guess is that perhaps, if your stack and application supported it, you could simply ...
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2answers
2k views

Host IPv6-only website and allow access to IPv4-only clients

Lets say site.example.com runs only with AAAA records, and I wish to access that site from IPv4-only network, and I don't want to do tunneling neither other protocols that masquerades IPv4 over IPv6 ...
6
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1answer
4k views

Method for assigning IPv6 ULA addresses to LAN

I'm finally embarking on the voyage that is IPv6. I am not sure however, on the best way of assigning a unique local address (ULA) to each host in my LAN. For IPv4 I prefer to have a DHCP server ...
1
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1answer
220 views

Cisco 3560G not passing IPv6 RA when VLAN without IPv6 address

Problem: When having VLAN without IPv6 address on L3 enabled switch, no RA is passed through VLAN unless there is IPv6 address assigned to the VLAN. Static assigments however are reachable fine. ...
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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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1answer
395 views

IPv6 default route

The IPv4 default route in CIDR notation is 0.0.0.0/0 translated to IP: 0.0.0.0 mask: 0.0.0.0 For IPv6 the default route in CIDR is ::/0. How is this transated ? Is it as below ? IP: :: mask: ::
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1answer
119 views

Doubt on handling mutable fields in IP header when computing digest or authentication data

I read RFC 4302, IP Authentication Header, Section 3.3.3, Integrity Check Value Calculation. In page 13, it is mentioned that the fields which are mutable during transit, like TTL or hop count, are ...
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1answer
510 views

How to configure a VLAN for all its client to get stateful IPv6 through a DHCPv6 server in the network on a Cisco C891F router?

Alright, so I've been trying this without any luck the whole day. How to configure a VLAN for all its client to get stateful IPv6 through a DHCPv6 server in the network on a Cisco C891F router? My ...
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3answers
1k views

How does multihoming work with ipv6?

What are the differences between multihoming in IPv4 versus IPv6? Can an enterprise request a provider-independent IPv6 address space from its RIR/LIR which can be advertised to multiple upstream ...
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1answer
742 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-...
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1answer
75 views

Would two hosts with arbitrary IPs communicate with /0 mask in the same subnet? [closed]

I'm studying for my networking finals and this thought experiment crossed my mind. I was told that as long as two hosts are in the same subnet they can communicate by using only ARP requests skipping ...
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2answers
704 views

SLAAC : What's wrong with this generated IPv6 address?

Consider this MAC : a4:ba:db:fe:b24b. The method "SLAAC" allows us to generate an IPv6 from this MAC: First we put fffe in the fourth and fifth bytes Then, we invert the 7th bit of the first byte. ...
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2answers
284 views

How do I determine the IPV6 address added to VXLAN when interface is set to up? [closed]

Setup: Currently working on a machine with Red Hat 7.2 (Red Hat Enterprise Linux Server release 7.2 (Maipo) to be exact.) I have a vxlan interface configured: # ip link add test.123 type vxlan dev ...
2
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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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2answers
186 views

Are all the private IPv6 addresses nonoverlapping? If yes, is Route distinguisher required for IPv6?

I am wondering if all the private IPv6 address non overlapping. And if yes, I am wondering if RD is required for IPv6 addresses. When two customer sites of an ISP are using same overlapping private ...
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2answers
2k views

pfSense: ICMP Ping allowed, but not possible

I have a pfSense 2.2.6 box that is connected with a WAN link that supports native IPv6. IPv6 is working great, and my clients can access IPv6 services on the Internet and also on the local network. ...
2
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1answer
76 views

How does IPv6 AH guarranties authentication?

IPv6 Authentication Header uses MD5 hash on the payload, the header, and unchanging fields of the IPv6 header and options to prevent sequence quessing attacks. But all these required information to ...
2
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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?
0
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1answer
579 views

High traffic caused by DHCPv6 [closed]

We have a medium sized network setup with multiple switches and one firewall (pfsense). We now have IPv6 since two months and sometimes can observe, that there is a huge amount of traffic on the ...
8
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1answer
1k views

What is the meaning of streamlined ipv6 header?

I don't understand what it is meant for "streamlined ipv6 header"? Could you please provide an example?
4
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3answers
390 views

What is IPv6 trying to fix with Router Advertisements (RA)?

It seems the situation with finding routers in IPv4 with DHCP was okay and now IPv6 has RA's and we have to worry about rogue RA, different vendors provide protection against it, etc. What is IPv6 ...
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2answers
491 views

How does data encapsulation work in the TCP/IP stack?

As a UDP segment traverses down the stack, each layer adds a header. What occurs for this to happen? Does the kernel do a bunch stuff then add the header? I am particularly interested in the ...
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1answer
60 views

Misbehaving host always uses the gw's MAC as destination: Violation of standard?

We have an appliance that always uses the IPv6 gateway's MAC address as the link layer destination address for all its outgoing IPv6 packets, even when the receivers IPv6 address is on the same subnet....
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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 ...
2
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1answer
72 views

Multhoming including incoming connections?

I am investingating the option of connecting our business network to 2 separate ISPs for redundancy. Since we have a couple of B2B services which need to be accessible from outside, in order to have ...
0
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1answer
4k views

Start with 192.168.67.0/24 and split it into 4 equal networks, what is the third usable IP address of the 3rd subnet? how do you solve this? [duplicate]

Start with 192.168.67.0/24 and split it into 4 equal networks, what is the third usable IP address of the 3rd subnet? how do you solve this?
0
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1answer
198 views

Openvpn and IPV6: how to configure it without knowing the server's IPV6 address

I'm using openvpn to connect to a network through a VPN and I use a ovpn file which is the following: dev tap persist-tun persist-key cipher AES-128-CBC auth SHA1 tls-client client resolv-retry ...
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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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4answers
3k views

DHCPv6 (with PD) client on Juniper SRX

OK, this one may technically be off-topic since I'm actually doing this at home, but I could easily see the exact same scenario arises in a small enterprise type of setup... Using an SRX210 to be a ...
5
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2answers
280 views

Network Address Translation

The below given diagram is a Static NAT implementation. To ping from an IPv4 client to an IPv6 client across the router we have to ping the IPv4-mapped address of the corresponding IPv6 client. For ...
0
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1answer
51 views

IPv6 create many gateways

We want to implement ipv6 on our network as we begin to offer our customers dual stack. We offer dedicated servers and we wish to give a /64 with each server. In one vlan, we wish to have 255 x /64 ...
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4answers
109 views

What is the common notation of multiple subnets

I store many IP-Addresses in a database. Is there any common notation for a group of IP-Addresses and subnet. Currently I dither between these notations: *.*.*.160/29 ?.?.?.160/29 ...160/29 x.x.x....
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1answer
495 views

Juniper EX IPv6 outside LAN isn't working

JunOS version: 12.3R11.2 Juniper EX switch with 2 VLANs: vlan 0: IPv4: 10.0.0.6/20 This vlan is used for private IP space vlan 1: IPv4: X.X.X.254/24 IPv6: XXXX:XXXX:X:XXX::ffff/64 This vlan is ...