Duplicate IPv6 SLAAC Routes on AlmaLinux 9.5: Causes and Solutions
In this article, we will discuss the issue of duplicate IPv6 SLAAC (Stateless Address Autoconfiguration) routes on AlmaLinux 9.5. We will cover the following topics:
What are IPv6 SLAAC Routes?
IPv6 SLAAC is a method of automatically configuring IPv6 addresses on an interface. It uses the Router Advertisement (RA) messages to advertise prefix information and other parameters. The interface then generates a link-local address and a global address using the advertised prefix and its interface identifier (IID).
Causes of Duplicate IPv6 SLAAC Routes
Duplicate IPv6 SLAAC routes can occur due to several reasons:
- Multiple routers advertising the same prefix
- A misconfigured network device that is advertising a prefix
- A device that has multiple interfaces connected to the same network
Impact of Duplicate IPv6 SLAAC Routes
Duplicate IPv6 SLAAC routes can cause several issues, including:
- Traffic loops
- Increased network traffic
- Network performance issues
Finding Duplicate IPv6 SLAAC Routes
To find duplicate IPv6 SLAAC routes, we can use the following command:
# ip -6 route show ::/0
default via fe80::21c:a9ff:fe0e:e39c dev ens1f0 proto ra metric 100 pref medium
default via fe80::21c:a9ff:fe0e:e39c dev ens1f1 proto ra metric 100 pref medium
In the above output, we can see that there are two default routes with the same next hop (fe80::21c:a9ff:fe0e:e39c). This indicates that there are duplicate IPv6 SLAAC routes.
Solutions for Duplicate IPv6 SLAAC Routes
The following solutions can be used to resolve duplicate IPv6 SLAAC routes:
- Disable SLAAC on some of the routers
- Filter RA messages to prevent duplicate prefixes from being advertised
- Disable SLAAC on some of the interfaces on the device
Duplicate IPv6 SLAAC routes on AlmaLinux 9.5 can cause several issues, including traffic loops, increased network traffic, and network performance issues. By identifying the cause of the duplicate routes, we can implement solutions to resolve the issue. We can use the ip -6 route show command to find duplicate IPv6 SLAAC routes.