Let’s keep going and finish IPv6 introduction.
A multicast address identifies a group of interfaces. Traffic, that is sent to a multicast address, is sent to multiple destinations at the same time. An interface may belong to any number of multicast groups. Multicast addresses are defined by the prefix FF00::/8.
To start using IPv6 in our labs, I decided to prepare a short introduction of it. As it is a broad topic I had to split it into several parts. Let’s start from the beginning.
Short IPv6 history
First IPv6 protocol specification was introduced in late 1995 in RFC1883, so it was 18 years ago! About one year later 6bone network was started as a virtual network over the IPv4-based Internet (using IPv6 over IPv4 tunneling). The mission of the 6bone was to establish the IPv6 environment for testing purposes. In 1999 IPv6 Forum was founded and registries started assigning IPv6 prefixes to ISPs. In 2000, many vendors began to bundle IPv6 into their mainstream product lines. 2009 – first serious IPv4 address shortage in developed countries.
What about IPv5?
Some time ago I wrote about interface policy-based routing PBR. Today I will show you example of local PBR configuration on Huawei AR routers. Local PBR allows you to forward packets through different interfaces or to different hops. Unlike interface PBR, local PBR is used for locally generated packets and classifies packets based on source addresses or packet lenghts.
Let’s look at the topology and configure as follows:
- Locally generated ICMP packets (with the size of 70-1300 bytes) will be sent to next hop IP address 172.16.0.2.
- Locally generated ICMP packets (with the size of 1301-1500 bytes) will be sent to outbound interface GE0/0/1.
I have never used it but it looks interesting. Arp-ping lets us to check whether a specified IP address or MAC address is being used in a LAN. Intrigued, I opened Huawei eNSP simulator to check this feature. Results are not fully satisfied. As arp-ping IP works correctly, I cannot say the same about arp-ping MAC. There are some problems with communication between router and hosts. It looks like router does not receive ICMP Echo Reply packets from hosts in the LAN. I checked the same between router and switch “labnario_SW2”. Results look promising. Let’s pass on to the lab.
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A short NAT (Network Address Translation) description based on AR1200 documentation:
Huawei AR1200 supports the following NAT features: static NAT, port address translation (PAT), internal server, NAT Application Level Gateway (ALG), NAT filtering, NAT mapping, Easy IP, twice NAT, and NAT multi-instance.
The number of private addresses is equal to the number of public addresses, so it does not save pull of public addresses.
Maps a public address to multiple private addresses.