ollyg
commented
3 weeks ago Hi @elbuit Thanks for opening an issue. This is unlikely to be Netdisco itself (as far as I can tell from code), and likely either SNMP::Info or even an issue in the Cisco platform (that is, a bug). There are some things you can do to see where the data is lost:
(just to note that in your original message above, you had an arpnip for the first output but a "discover" for the second, which I assume was a mistake)
Netdisco uses ipv6_n2p_mac() and ipv6_n2p_addr() from SNMP::Info for the v6 table. You can see the underlying data:
~/bin/netdisco-do show -d XXX.XXX.100.225 -e ipv6_n2p_mac
~/bin/netdisco-do show -d XXX.XXX.100.225 -e ipv6_n2p_addrHowever each of these methods actually tries three ways to get the v6 table from the device. I wonder if it's picking the "wrong" one (there is a first-success logic, but it could be missing the best option that way).
# in order:
~/bin/netdisco-do show -d XXX.XXX.100.225 -e c_inet_phys_addr
~/bin/netdisco-do show -d XXX.XXX.100.225 -e ip_n2p_phys_addr
~/bin/netdisco-do show -d XXX.XXX.100.225 -e i6_n2p_phys_addrThere's also another method which shows IPv6 interfaces:
~/bin/netdisco-do show -d XXX.XXX.100.225 -e ipv6_n2p_ifMaybe try each of these, with and without the v4 address applied, and see if they return a low or a high number of records?
I would not be surprised if it's a Cisco platform bug. But that doesn't mean we can't work around it in SNMP::Info. We just need the reproducing test case.
regards Oliver.
elbuit
I've several Cisco 9500X and netdisco can't get IPv6 neighbours if ALL interfaces VLAN are only IPv6.
If I add a IPv4 address to a int Vlan then netdisco can do the arpnip correctly on that interface and also the rest of them, although these vlan interfaces are IPv6 only configured.
That router had IPv4 only vlan interfaces, and the arpnip in IPv4 works perfectly, is when you have IPv4/IPv6 only Vlan interfaces.
Your Environment
App::Netdisco 2.78.0 SNMP::Info 3.970.1 DB Schema 88 PostgreSQL 11.00.17 Perl / Python 5.36.0 / 3.11.2
Device information
Cisco C9500-32C Cisco IOS XE Software, Version 17.15.01
Example:
With all Vlan interfeces IPv6 only:
Then I added a IPv4 on a Vlan Interface (192.168.160.1):
And netdisco gets IPv6 subnets and neighbours for all the Vlan IPv6 Interfaces.