PR: https://github.com/vyos/vyos-1x/pull/449

One more question/proposition.
Before ethX is added to the bond its IP addresses are being removed (that's good). Then, when ethX is removed from the bond it is being left as disabled. If we manually re-enable that interface the interfaces-ethernet.py script is run and it configures all its settings (including IPv6 link-local address). Therefore, maybe it is not that bad idea to leave the interface disabled when it leaves the bond. So, what if we just add a warning message to inform users that bond leaving interface will stay disabled until it is manually re-enabled.

PR for 1.2: https://github.com/vyos/vyatta-cfg-system/pull/124

PR: https://github.com/vyos/vyos-1x/pull/442

I just did a few more tests and the reason why IPv6 is gone is that the interface is being automatically disabled after it leaves bond membership. I will change the description accordingly.

@jjakob, thanks for your opinion. What if we just add a couple of lines into the apply() function in the interfaces-bonding.py:
https://github.com/vyos/vyos-1x/compare/current...L6NqLW:T2515?expand=1

PR created, https://github.com/vyos/vyos-1x/pull/431.

@jjakob, yes, thank you.
PR for 1.3: https://github.com/vyos/vyos-1x/pull/434
I will summit PR for 1.2 once 1.3 is released and tested.

@runar, thanks for clarification! I will change the initial description accordingly.

@dmbaturin @c-po
Not sure why did we merge these PRs. The isc-dhcp-relay does require at least two interfaces to work. This was discussed in details in T1276 and T2408.
As result the latest documentation is inaccurate what could make users confused.

I forget - I did not observe any disability in router behavior. At least with simple configuration that I tested.
Observed messages may be a bit worrying for users at the very beginning of using VyOS.

This can be mitigated by:

1. add to ALL ipv4 peers "address-family ipv4-unicast" set

I confirm that this can be mitigated by:

1. add to ALL ipv4 peers "address-family ipv4-unicast" set

set protocols bgp xxxxxx neighbor x.x.x.x address-family ipv4-unicast

2. disable default ipv4 peering

set protocols bgp xxxxxx parameters default no-ipv4-unicast

@Gislaved, I have just tested it on the KVM (proxmox) with VirtIO and I coudn't reproduce it. It works with exactly the same defects as I mentioned in my previous message. Tested on the both LTS and 1.3-rolling-202005031216.

Enhancement created.
Question to ISC submitted (https://gitlab.isc.org/isc-projects/dhcp/-/issues/104)

@ddiguru
I confirm all the issues that you have observed. I was able to reproduce them in the both our LTS and currect rolling releases.

1. Issue with a wrong giaddr address. This sounds like a bug in the isc-dhp-relay package. Fortunately, those extra packets with a wrong giaddr address could be eliminated in newer versions by using "-id" and "-iu" instead of muliple "-i" options. isc-dhcp-relay allows for this since v4.3.5. I will create a Feature Request to modify the VyOS config syntax and isc-dhcp-relay config file accordingly. In the meantime I will try to confirm with ISC people that this indeed is a bug.
2. Issue with duplicate packets. isc-dhp-relay seems to unnecessarily relay unicast packets (I have no idea why it does so). That's why you see all unicast packets doubled. Looks like another bug :) The good news is that it is more cosmetic issue. I already submitted the ticket for it (https://gitlab.isc.org/isc-projects/dhcp/-/issues/102)

This is solved in both the current LTS and rolling releases.

The issue has been solved by the above merge.

Test results on the VyOS 1.3-rolling-202004020117:
Basically, the DHCP option 121 is handled as expected but two issues were observed i.e.:

1. Static routes advertised by the DHCP server in option 121 are not automatically removed from the FIB when the "address dhcp" setting is removed from the interface. Disable/enable the interface doesn't change anything. The only option to get rid of them is to restart the router.

A similar behavior is observed when the "address dhcp" config is replaced with static IP address in one go. In that case disable/enable the interface at least makes them removed from the FIB but they are still present in the FRR as "inactive" . The only option to get rid of them is to restart the router.

The automatic helper assignment is enabled in both the LTS and the current rolling releases. The only thing that is needed to make the TFTP working is to allow the udp/69 and "related" traffic.

The automatic helper assignment is enabled in both the LTS and the current rolling releases. The only thing that is needed to make the FTP working is to allow the tcp/21, "related" and "established" traffic.

I was not able to recreate that issue. Both /24 and /8 networks were tested.
All the tests have been done on the VyOS 1.3-rolling-202004020117.