Questions tagged [ipv6]
For questions about Internet Protocol version 6 (IPv6); as specified in RFC 8200.
412
questions
4
votes
1answer
114 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 ...
1
vote
1answer
68 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
33 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 ...
0
votes
0answers
48 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
35 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 ...
1
vote
2answers
57 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
21 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 ?
1
vote
1answer
93 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
63 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 ...
0
votes
1answer
22 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
26 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 ...
1
vote
0answers
18 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
48 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
759 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
29 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
84 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
18 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
19 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
208 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
48 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
15 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
65 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
111 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
36 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
65 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
64 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. ...
1
vote
2answers
417 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
49 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
48 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
471 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
114 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
42 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
244 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
86 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
78 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 ...
1
vote
1answer
130 views
Why is an IPv6 interface required to have a link-local address?
According to Link-local address on Wikipedia:
In IPv4, link-local addresses are normally only used when no external, stateful mechanism of address configuration exists, such as the Dynamic Host ...
0
votes
1answer
91 views
Extra IPv6 Addresses - where are they coming from? [closed]
I recently got assigned a block of IPv6 addresses by my ISP. I've set it up with prefix delegation and it works just fine. When I plug a NIC in on the network it quickly picks up an IPv4 address from ...
0
votes
2answers
93 views
IPV6 static Routing
I'm new to networking and I'm currently learning about IPv6 in static routing. I set up an environment in Cisco Packet Tracer like this: have connected two routers with serial medium , each router ...
2
votes
2answers
466 views
What Does a Private IPV6 address look Like?
I'm doing a presentation on how the internet works, and I'm wondering if there is even such a thing as a private IPV6 address. If so, what does a private IPV6 address looks like?
1
vote
1answer
202 views
What is the last usable address in an IPv6 network
IPv6 does not have broadcast, so is the last address usable? Besides it being long, is it bad practice to actually use it?
For example: A:B:C:D::0/64 starts with A:B:C:D:0000:0000:0000:0000 and ends ...
0
votes
2answers
332 views
IPv6 Extension Headers and UDP/TCP/ICMPv6 Checksums
Should the checksum for IPv6 packets (UDP, TCP, ICMPv6, etc.) change if extension headers are present? For example, will a UDP packet without a Hop-By-Hop extension header have a different checksum ...
0
votes
0answers
44 views
IPv6 - link-locals mess
I am implementing IPv6 in my network and for now I have my own routable IPv6 /48 block, Cisco routers, Cisco switches, OSPF between them and several hosts. Its all working fine, but there is something ...
25
votes
3answers
6k views
Will IPv6 make private IP addresses become obsolete?
Will it still be useful to make use of private IP addresses with IPv6?
1
vote
0answers
43 views
If a server has both IPv4 and IPv6 addresses, how does the DNS determine which to return? See the following example [closed]
These Pings were done at different times of the same day:
C:\Users\LPress>ping www.ucla.edu
Pinging gateway.lb.it.ucla.edu [164.67.228.152] with 32 bytes of data:
C:\Users\LPress>ping www.ucla.edu
...
2
votes
1answer
103 views
IPv6 SLAAC and Static DAD
I started learning about IPv6 and I wonder what happens when you mix SLAAC and static addresses in the same /64.
My current understanding is as follows:
Machine A with a statically configured ...
1
vote
1answer
40 views
ipv6: I can ping only 1 interface within same network even with static route
This is how I set up a static route.
R1(conf): ipv6 route 2004:DB8:2233:23::/64 2001:DB8:1122:12::2
With this, I can ping to 2004:DB8:2233:23::2 (S2/2 on R2) but not to 2004:DB8:2233:23::3 (S2/2 on ...
1
vote
2answers
421 views
Can link local addresses be used for transit networks without breaking routability?
I am asking this because my ISP uses SLAAC/DHCPv6 to assign addresses to clients. Firewalls, no matter what brand/name/type get a link local IPv6 address complete with a link local gateway AND clients ...
1
vote
1answer
104 views
How Many Extension Headers Can an IPv6 Packet Have?
How many next-header extensions can an IPv6 packet contain?
I read here that it can contains:
None, one, or more.
which isn't very informative.
Below is a reference to an IPv6 packet I'm looking ...
