Internet Protocol version 6 (IPv6). This tag is for all aspects of IPv6, basic concepts, migration strategies, translation mechanisms, etc.
5
votes
1answer
35 views
Configure External Interface for DHCPv6 client on Cisco IOS
What are the necessary steps to configure IOS 12.4(25f) to support IPv6? Comcast is the ISP, and I'll be using a Server 2012 box for internal DHCPv6.
I'll need to grab a DHCPv6 address from Comcast ...
5
votes
1answer
40 views
Blocking IPv6 RA advertisements on Juniper EX series switch
How do I go about blocking IPv6 RA advertisements on access ports on a Juniper EX series switch? I know that Cisco offers ra-guard as an option much like bpdu-guard on spanning tree, I am just not ...
1
vote
2answers
84 views
IPv6 address range [closed]
The number of address for IPv6 is (2^128). However, this does not define the number of unique devices that are addressable. There are certain class of address that are reserved, for instance the link ...
14
votes
4answers
860 views
Why does ipv6 specify 128 bit address, when there are only 48 bits in MAC addresses?
So, I'm reading for a networking exam, and I'm just wondering if I have missed something basic. Is there a need for more ip addresses than MAC addresses, and how would a node with one network adapter ...
7
votes
6answers
423 views
Best practice for dual-homing site with two ISPs?
I am subscribed to two ISPs, a fast expensive one and a cheap but slower one. They use different technologies, cable and ADSL, so there isn't much of a single point of failure, and all my comms ...
3
votes
2answers
60 views
address-family ipv6 on Cisco 3560G
Is anyone aware of an IOS version for the C3560G that supports configuring a neighbor to exchange IPv6 routes? Apparently 12.2(37)SE Advanced IP Services can't do it - as soon as you try to activate ...
9
votes
1answer
109 views
ASA5505 and IPv6 over a PPPoE Link
I see a lot of conflicting information about whether or not a Cisco ASA (5505 in this case) can use IPv6 over a PPPoE connection.
I see official Cisco documentation making it look easy, but I see ...
6
votes
2answers
144 views
What is the maximum prefix size routed in the IPv6 Internet?
In v4, most of the operators filter BGP updates for prefixes longer than a /24, to preserve the size of the full view.
What about IPv6 ? Is there such "convention" that stands out ?
9
votes
4answers
637 views
Time to switch to IPv6?
I am thinking of upgrading our networking situation and am considering a migration of IPv4 to IPv6. Is it too soon to be considering this move as it looks like much of the networking gear and OSen ...
10
votes
4answers
144 views
How to choose a BGP router ID when using IPv6 only?
Usually, when using BGP, you can choose (or your device chooses four you) a router ID from one of your assigned public IP addresses.
Now, let's admit you only run IPv6. As the router ID is still a 32 ...
7
votes
4answers
319 views
What IPv6 prefixes should never be routed?
Seems clear to me that the Link Local, and Unique Local, addresses should at least be filtered.
Is there anything other than LLA/ULA that should be filtered?
For LLA, is it standard practice to ...
5
votes
3answers
97 views
Selecting IPv6 Unique Local Addresses (ie, choosing least-sig 40 bits)
We started with fec0::/10 for site-local addresses -- but that is now deprecated. Instead, we now have fc00::/7 reserved, with fd00::/8 dedicated to /48 nets for Unique Local Addresses.
What's the ...
4
votes
3answers
100 views
Mitigating bad/malicious IPv6 RA announcements
In a Cisco environment (ISR-G2), how do I prevent, or mitigate, incorrect RA announcements?
I see Cisco has "IPv6 RA Guard"... But does that just run on the router and "fight back" with correct RAs? ...
3
votes
3answers
304 views
Migration from IPv4 to IPv6 strategies
As everyone is aware we are out of IPv4 addresses and soon (if not already) we shall be moving on to IPv6. What are some good strategies and practices to migrate a complete IPv4 network onto IPv6?
5
votes
2answers
129 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 ...
-3
votes
2answers
143 views
Transitioning a Network-Backbone to IPv6 while keeping IPv4-Connectivity between the Endpoints [closed]
Let's say you have a bunch of separate but fully internally addressable Networks (Building 1, Building 2, Building 3, ...), that run on an IPv4-Basis.
What would be possible ways, to switch the ...
15
votes
3answers
383 views
Why is fe80::/10 reserved for link local addresses when fe80::/64 is actually used?
I understand that IPv6 reserves the fe80::/10 prefix for link local addresses, and that hosts select an address with a /64 prefix.
Why is the reserved space so much larger than what is actually used ...
39
votes
8answers
11k views
IPv6 address space layout best practices
I'm comfortable with IPv4 address space allocations. By which I mean: Given services to plan for, or an organization to network, I have a good grasp of how to plan IP address space usage. (or at ...
