Questions tagged [icmpv6]

For questions about ICMP version 6 for IPv6, where ICMPv6 is defined in RFC 4443. It is an integral part of IPv6 and performs error reporting and diagnostic functions (e.g., ping), and has a framework for extensions to implement future changes.

Filter by
Sorted by
Tagged with
3
votes
1answer
40 views

How to handle IPv6 Extension Header Options with action = 01

RFC 8200 section 4.2 states that if a node does not recognize an option type, that node must do some action depending on the 2 higher order bits of the option type. When the higher order bits are 01, ...
2
votes
2answers
55 views

How to handle ICMP-in-IPv6 or ICMPv6-in-IPv4?

Since ICMP and ICMPv6 have different IP protocol numbers, it's technically possible for an IPv4 host to receive an ICMPv6 packet or for an IPv6 host to receive an ICMP packet. Is the host's behavior ...
6
votes
4answers
781 views

OSI layer of Neighbor Discovery Protocol

NDP operates using ICMPv6 and, even though ICMPv6 messages are encapsulated in payload field of IPv6 datagram, ICMPv6 and ICMP are usually considered as network layer protocols. At least, on Wikipedia ...
2
votes
1answer
34 views

Global Unicast in IPv6 Neighbor Discovery

I have a very small pcap file in which Neighbor Discovery is performed for Global Unicast Addresses. That is, IPv6 addresses of both neighbors as I can see in Wireshark start from 2001:. Both IPv6 ...
5
votes
1answer
477 views

How does router advertisement in IPv6 avoid IP conflict?

If a router advertisement sends the range of subnet, and the client can choose an IP from it, how is there no conflict with another client that has chosen the same address?
3
votes
1answer
738 views

Network flooded with ICMPv6 Multicast Listener Report Packets

I recently noticed that 3 out of 4 Unifi APs kept reaching 100% CPU usage. When I jumped onto the networks and took a Wireshark capture I noticed 1000s of these packets being sent in just a matter of ...
1
vote
1answer
130 views

How can IPv6 host know default router's IPv6 address using RA?

I know an IPv6 host will send Router Solicitation (RS) messages, and a router on the link will reply Router Advertisement (RA) messages. In the RA message, there is the Source Link-Layer Address and ...
1
vote
1answer
324 views

Enabling Multicast Listener Discovery (MLD)

Do standard NICs that support IPv6 have the ability to perform MLD? Essentially I understand MLD, but am struggling to find if it needs to be configured or if it is enabled by default on a host. Just ...
1
vote
0answers
212 views

Force ICMPV6 packet using envelope icon

I play with Packet Tracer 6.2 using IPv4 and IPv6 addresses, trying to ping routers using the envelope icon. When both routers are IPv4 or IPv6, clicking envelope correctly chooses between ICMP and ...
5
votes
2answers
3k views

Calculating checksum for ICMPv6

Referring http://www.faqs.org/rfcs/rfc1071.html, I try to deduce the c code for calculating the checksum for ICMPv6. But check with the checksum parse by wireshark, I find that the answer got from my ...
1
vote
3answers
587 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 ...
2
votes
0answers
596 views

IPv6 Neighbor Discovery procedure with a ping example

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 ...
1
vote
1answer
675 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, ...
1
vote
1answer
174 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. ...
6
votes
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 ...
4
votes
3answers
2k views

Entirely wireless network being taken down by ICMPv6 neighbor solicitations

We are in our second week of school, now, and starting yesterday we started receiving complaints about slow wireless internet. After some investigating, we found out that our entire wireless network ...
18
votes
1answer
2k views

Why do some common traceroute implementations default to using UDP probes?

I was recently troubleshooting a network connectivity meta-problem, in that I knew a given destination was reachable, but I was not able to demonstrate that with traceroute because the path went cold ...
6
votes
1answer
482 views

IPv6 replacement for ICMP timestamp

Does any standard IPv6 protocol has anything analogous to an ICMP timestamp message?
9
votes
2answers
5k views

Is TCP maximum segment size (MSS) “clamping” compatible with IPv6?

With IPv4, TCP MSS "clamping" (a network device editing the MSS value in a TCP header) can help when path maximum transmission unit discovery is not working. (e.g., when ICMP is being blocked ...