Questions tagged [ipv6]
For questions about Internet Protocol version 6 (IPv6); as specified in RFC 8200.
424
questions
0
votes
1answer
23 views
Is it possible to do SLAAC with Route Advertisement *without* default-route? [closed]
I have a router with IPv6-ULA networks. It's running Linux with Systemd-networkd if that matters.
Now I'd like to auto-configure clients in one network so that they will have an address in one of the ...
1
vote
1answer
32 views
Why solicited-node multicast address while all-node multicast address can do the same thing?
Why bother plugging in the last 24 bits of the sender's unicast address into the solicited-node multicast address while all-node multicast address can achieve the same thing? In my view, this move is ...
2
votes
2answers
35 views
Does it require a DAD when generating link-local address in IPv6
In IPv4, link-local addresses are checked to be unique using an ARP request. But in IPv6, as it is generated by a EUI-64 or hash. It is assumed to be unique (I suppose). But does it require a DAD (...
0
votes
1answer
41 views
What is the reason behind not returning unused IP addresses? [closed]
There are several companies out there with one or more /8 IP addresses, for example:
DoD has more than 200 million,
HP has one /8 (>16 million),
Apple has one /8,
General Electric has one /8,
IBM ...
0
votes
2answers
23 views
Calculating Checksum for ICMPv6 Packet
I have a packet that has a checksum of 0xffff, and a calculated checksum of 0x0000. I know in UDP, a checksum of 0x0000 is not allowed, and is instead replaced with 0xffff, thus the packet should be ...
0
votes
5answers
219 views
If IPv6 exists, why do we still pay for static IPv4 addresses?
Given that there is some ridiculous number of IPv6 addresses per every single person on the planet, why do ISPs still charge for IPv4 addresses? Why not just give the user an IPv6 address?
Is it ...
4
votes
1answer
524 views
Which one right, UDP has 508 or 512 bytes payload limits?
We know the size guarantees the datagram won't be fragmented in IPv4 is maximum 576 bytes. But the size when use UDP header 8 bytes and if we take UDP payload 512 bytes and choose maximum header size ...
0
votes
1answer
36 views
Do IPv6 addresses have better persistence with DHCPv6?
I have a LAN with about 25 devices that occasionally grab each other's IP address via DHCPv4. I know there are certain lease time limits and it can be set to very long periods to work it around to an ...
3
votes
1answer
87 views
Are IPv4 type of service and IPv6 traffic class equivalent to each other or is traffic class IPv6 specific? [duplicate]
IPv6 has a traffic class field. According to the specification it is an IPv6 length, out of which first 6 bits are called code point or differential services code point (DSCP) and the last 2 bits are ...
2
votes
2answers
88 views
Is it possible for TCP can accept out of order segments?
TCP is connection-oriented protocol whereas IP isn't connection-oriented protocol. Any packets before sending into transport layer sorted operation must have been done in network layer. That's why we ...
5
votes
2answers
185 views
Why can IPv4 and IPv6 use strict source routing(in options field) and flow label respectively inspite of connectionless protocol?
In IPv4 option field one field option is source routing option this means packet will always be routed by router Or not. Packet can also be routed by source such routing is known as source routing. ...
1
vote
1answer
35 views
How to configure IPV6 /53 subnet on packet tracer?
I have tried configuring a Ipv6 subnet address 2001:0dce:0000:0000::1/53 into the router interface.
It works but when the I tried setting the auto-configuration button on the PC connected to this ...
1
vote
4answers
99 views
IPv6 addresses plan and allocation
I read at several places that ISPs should allocate a /48 (or /56) IPv6 addresses blocks to end users
Wikipedia for instance
The RIRs assign smaller blocks to local Internet registries that ...
4
votes
1answer
127 views
Traffic sent to GRE Tunnel fails, but GRE Tunnel is up and OSPF adjacencies are formed
NEW INFO_7-12-21
R1#sho ipv6 rout 2001:db8:B2:200::2:2
Routing entry for 2001:db8:B2:200::2:2/128
Known via "static", distance 1, metric 0
Route count is 1/1, share count 0
Routing ...
2
votes
1answer
156 views
Static IPv6 Route on Ubiquiti EdgeRouter for my own /64
I am colocating some hardware in a local datacenter, and I'm trying to get IPv6 going.
My datacenter has assigned me a /64, but they have given me a gateway address within that /64.
The gateway (that ...
2
votes
1answer
45 views
EUI-64 on a loopback address
A loopback address does not have a MAC address. How then does a loopback interface get assigned an EUI-64 address? I ran an example on packet tracer, and the loopback interface successfully acquired a ...
1
vote
0answers
53 views
Why cant my network send packages but piv6 pings go through?
I have the following network:
My routing is as follows:
Device configuration for ISP:
Building configuration...
Current configuration : 1388 bytes
!
version 15.1
no service timestamps log datetime ...
0
votes
2answers
39 views
How to create a mapping between TCP segments or IP packets or fragments and TCP Windows? [closed]
I am searching for a method how I practically can determine the segments within a TCP window both when sending and receiving them?
I want to modify IP packets per TCP window.
I already looked into the ...
2
votes
2answers
64 views
Unable to add an abbreviated IPv6 to a Cisco router
I am very new to networking and playing around with GNS3. I am trying to configure a router to have 2 IPv6 addresses in a single interface (as far as I understood, this is possible with IPv6)
I ...
-1
votes
1answer
22 views
why is the adress prefix for global unicast adresses in ipv6 considered 3 bits?
global unicast adresses in ipv6 always start with number 2 or 3, but 2 or 3 takes only 2 bits , and the whole adress is represented in hexadec which takes 4 bits not 3, so why the prefix is 3 bits ?
2
votes
1answer
277 views
I can't ping the gateway IP (fe80::1) from the internal port in my fortigate 60f firewall
I am using a fortigate 60f firewall. I have configured it for both ipv4 and ipv6. I have used the SD wan (by adding wan1 and wan2) for load-balancing. Moreover, I have configure a default static route ...
1
vote
1answer
69 views
How does a device receive default gateway IP address?
When and how does a device get information about default gateway in LAN? I know you can define default gateway statically, but which protocol is used when it is not statically defined? Is it from ...
1
vote
1answer
24 views
Can servers derive the user IPv6 block of an address?
Internet Service Providers (ISPs) assign users large IPv6 blocks (~/64) containing millions of IPv6 addresses. If a user was to ping a server using 2 different IPv6 addresses from his given IPv6 block,...
0
votes
1answer
33 views
Why does a Cisco router advertise a prefix with NDP RA when it has an address in that range?
If I write
interface Vlan1
... {ipv4 config} ...
ipv6 address 2001:DB8:5432:101::/64 eui-64
ipv6 address FDAA:DB8:5432:101::/64 eui-64
ipv6 enable
ipv6 nd prefix 2001:DB8:5432:101::/64
ipv6 nd ...
2
votes
0answers
26 views
Can I route DHCPv6 & Router-Advertisements through another router? [closed]
I have asked this question on Super-User, though I'm not sure, it's the best place. 1
I believe this Exchange is a more appropriate place to ask:
I have a dual router setup (two routers behind each ...
3
votes
1answer
54 views
Recommended IPv6 prefix size for PPP to a single host?
I am using PPP to create a IPv6 connection to a remote host.
What is the recommended IPv6 prefix size for a single host at the other end of the PPP connection?
Should it be /128, because there is ...
5
votes
2answers
849 views
Can a client-side outbound TCP port be reused concurrently for multiple destinations?
Can a client-side outbound TCP port be reused concurrently for multiple destinations?
If it's possible, this would let NAT gateways milk an IP Address much more, and make it practically impossible to ...
0
votes
0answers
30 views
ECT Marked ICMP Responses
For ongoing research I'm conducting, I'm measuring the modification of ECT fields of the IPv[46] header. To do this I'm relying on ICMP quotations to inspect what packets 'look like' as they traverse ...
3
votes
2answers
100 views
IPv6 Prefix Delegation & propagation through an organisation
IPv6 Prefix delegation is designed to allow an ISP to give an organisation a block of addresses to issue throughout their network. However, enterprise networks extend beyond a single tier of devices, ...
0
votes
0answers
19 views
Why did we not run out of IPv4 adresses yet? [duplicate]
I know how IP addresses work and I also understand the reasons why there is a natural limit to those addresses, as well as the solution to that problem. Officially, we have ran out of IPv4 addresses ...
1
vote
1answer
20 views
Ping6 replies go to a different interface [closed]
Server A has two interfaces (i1 and i2) with the same IP on them, say fd11:1111:1111:1111::1/48.
Server B has the same two interfaces with the same IP on them, say fd11:1111:1111:1111::2/48.
When ...
0
votes
1answer
218 views
Why DNS services Like google public DNS and Cloudflare 1.1.1.1 has ipv6 versions?
I understand the need for ipv6 as we ran out of ipv4 but dns resolvers like google and cloudflare already have ipv4 addresses for resolving dns and i don't see compatibility as a reason either because ...
0
votes
1answer
49 views
Need a little clarification with NAT and IPv6
I understand NAT exists to not exhaust all the ipv4 addresses so there is no need for it with ipv6. So with ipv6 having an unimaginable amount of addresses, will every device have its own public ...
1
vote
1answer
60 views
Confusion regarding possible IPv6 Link Local address prefixes
I have trouble understanding how many alternative link local IPv6 address prefixes may exist.
I know that the prefix is fe80::/10 which implies that the first 10 bits must be static as:
| 10 ...
1
vote
0answers
19 views
Segment Routing Encapsulation on Client Interface? [closed]
I wanted to test SRv6. Always between two clients (client 1 <-> client 2).
If I do the encapsulation on the client everything works smooth as expected.
Client 1 (encap SRv6 Tunnel) <- 2001::/...
0
votes
2answers
71 views
Is NAT66 a Viable Option to Protect Client?
Due to the addressing scheme of IPv6, each client now is able to get and directly use Globally-Routable Address (GUA) from the ISP. But that poses bigger security threat because attacker can directly ...
0
votes
2answers
149 views
Why cant't IPSec's Transport Mode ESP be used in NAT64 although ESP doesn't sign the new IP header?
In RFC6146 stated:
Any protocols that protect IP header are incompatible with NAT64. This
implies that end-to-end IPsec verification will fail when the
Authentication Header (AH) is used (both ...
1
vote
1answer
48 views
Why does CLAT in 464XLAT architecture use Stateless NAT64 instead of Stateful?
As of my understanding, stateless NAT is using 1:1 translation, meaning it needs one IPv4 address for one IPv6 address vice versa, thus not preserving IPv4. Since the CLAT is supposed to be router/...
0
votes
1answer
71 views
BGP unnumbered on P2MP link
I'm wondering what will happen if BGP unnumbered session is configured on a link that has multiple routers on the other side which are both IPv6-capable and will both reply on RS and produce RA ...
1
vote
1answer
87 views
GNS3 can not ping from ethernet interface to serial interface
So I am doing a Lab for one of my classes involving ipv6 and routing using EIGRP. When I set-up the network and assign the router interfaces with IPV6 address I get an issue pinging the whole network. ...
2
votes
2answers
584 views
General: What is a dynamic gateway, how does it work, where is it used?
I saw this option in my OPNsense gateway configuration, and was hoping someone could shed light on what it is, exactly:
Dynamic gateway policy: [YES/NO]
This interface does not require an ...
0
votes
1answer
87 views
How do I know when an AAAA record is required? [closed]
I'm trying to wrap my head around DNS. My biggest issue right now is understanding when an AAAA record is required.
Recently, I was asked by a colleague to point a subdomain from Server A to Server B....
-1
votes
1answer
49 views
IPv4 and IPv6 Source Address field
Both the IPv4 and IPv6 headers contain the source address field.
What are the reasons for including this field?
Is it for to trace which who sent this packet if it get's lost?
0
votes
1answer
569 views
How is ICMP Packet Too Big handled in IPv6?
I am trying to comprehend the way packets fragmentation works in IPv6.
As far as I understand it, IPv6 routers never fragment packets: upon receiving a packet whose size is bigger than the MTU of the ...
1
vote
2answers
148 views
Why does IPv6 NS not use unicast address but multicast
This is a follow up of Why not put unicast address in IPv6 packet containing NDP neighbor solicitation instead of solicited-node multicast address?
The accepted answer makes no sense.
It states the ...
1
vote
1answer
43 views
Brocade OSPFv3 Routes are not installed
I am trying to deploy OSPFv3 across our network. However a few routers do not install the OSPFv3 route's to their routing tables. For example, this router is able to ping a certain host on the network....
0
votes
1answer
266 views
Why is the IPv6 address I'm getting from whatismyipaddress.com wrong? [duplicate]
So I've portforwarded my machine using the graphical interface provided by my router. This interface also gives me a public IPv6 which I can use to communicate with my machine through the internet. ...
0
votes
1answer
93 views
ASSIGNED or AGGREGATED-BY-LIR status of IPv6 subnet used for Virtualisation
According to the RIPE NCC IPv6 Basics training slides the ASSIGNED status should be used for your own infrastructure and individual (large) assignments to customers. The AGGREGATED-BY-LIR status ...
7
votes
5answers
2k views
How does the shortage of IPv4 public IPs influence existing firewalls?
I came to know recently IPv4 public IP address pools are going to be exhausted soon. If IPv6 addresses are fully in use, all device vendors like Cisco, Fortinet, Palo Alto have to redesign their ...
3
votes
1answer
79 views
What are usecases for IPv6 link-scope anycast?
IPv6 Neighbor Advertisement messages have a flag called Override, see RFC4861. It toggles, whether the receiver of the message should remove other link-layer addresses for the same IPv6 target address ...
