NBN DHCP leases.

[D Burgess]

After getting a new IP address 3 times in 1 hour, I find that Optus
NBN (HFC) provides a DHCP lease time of 5 minutes. (I'm told Telstra
is 10 mins)

ABB have a 30 minute DHCP lease time..

If it was 5 hours or 5 days it would seem reasonable. But 5 minutes
seems to be using DHCP as a heartbeat.

Does anyone know why the lease times are so small?

[Timothy Rice]

> ABB have a 30 minute DHCP lease time..
>
> If it was 5 hours or 5 days it would seem reasonable. But 5 minutes
> seems to be using DHCP as a heartbeat.
>
> Does anyone know why the lease times are so small?

I'm with ABB. I actually found the half-hour wait quite inconvenient when
switching to a different device.

I was wondering why dhcpcd wasn't picking up an IP address on the new
router. It took a call to support to learn that I had to wait for the
half-hour session to expire.

~ Tim

[D Burgess]

Surely that is your new routers problem rather ABB.
The routers DHCP client should ask for an address, yes/no?

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D Burgess

[Timothy Rice]

On Tue, Oct 01, 2019 at 05:31:37PM +1000, D Burgess wrote:
> Surely that is your new routers problem rather ABB.
> The routers DHCP client should ask for an address, yes/no?

It's a router I built myself. It uses dhcpcd to request a lease. It
couldn't immediately request a lease because the session hadn't expired.

After the session expired, dhcpcd received a lease as expected. Also, the
router was able to request leases from other routers without any problems.

I suppose "sessions" (ABB's terminology) aren't the same as dhcp leases,
but they seem to be related from the ABB POV.

~ Tim

[Gary Pope]

I'm with AussieBB and they're great so far (since 16th Sept only)...
Answer any question well. But we did have an outage requiring ABB to
call in NBN and I suspect the fault was cloers to the Exchange then
anywhere near my place with HFC.
But to the question at hand, my experience on the day of repairs might
throw some 'timing' light on this discussion.

I happened to return home the day after logging the fault, and it was
just co-incidental that I reckon I caught the CM820 NBN modem doing some
test loops with the NBN technicians. My modem had been in a 4 minute
cycle of:
- re-powering,
- awaiting a connection to the DOWNLOAD link
- never getting the above, so DOWNLOAD and UPLOAD flash blue in error
- and the whole retry cycle happens again.

But when I walked in on that testing day, I observed that the DOWNLOAD
link had goone steady green at last, and the NBN modem was then testing
the UPLOAD link and finally settled to ONLINE. Result: all 4 lights
green.

So I jumped onto a LAN box to see if I had internet, but alas , not
yet. But what observed really puzzled me. The NBN modem had presented
me with a WAN IP of 192.168.100.11. Yes, a private IP on the WAN!.
I could ping it from my LAN side of my firewall thru to that WAN IP,
and also guessing there must have been some class C subnet of
192.168.100.x in play, I test pinged successfully over the WAN to
192.168.100.1

At that point I rang ABB Support to enquire what was the go, and we
both came to the conclusion that the NBN engineer must have placed us on
some test circuit to split the exchange to me, versus the exchange to
the world,
to narrow down the failure point, and the technician must have been
running a simulation WAN network of 192.168.100.x

Within 15 minutes of all this observation and calling ABB to fathom out
what was going on, the NBN link dropped entirely, (probably because of
the NBN technician completing his testing), and the NBN modem started
going thru the recycle phases again.

I gave everything about another 15 minute to settle down, but my
pfSense box was still sitting there with a DHCP lease of
192.168.100.11 and now, with no ping connection to the WAN at all.....

IE: the NBN modem had restarted, the pfSense box was of the opinion
that the WAN IP was still the old one....

I had to force a WAN request on the pfSense box, in order to get my
static IP properly again, which is delivered as a dynamic IP, but
always the same (for which we pay the $10 fee... which is fine).

My observation has left me with the concern that a firewall reset of WAN
is required in the even of an NBN failure down the HFC line......
OR: perhaps Timothy's 30-minute observation is what I should have been
more patient to await.....


Still some unexplained matters here, I believe..... but the overall
setup my end wasn't self-curing fast enough in my opinion....

Gary

[Timothy Rice]

> Still some unexplained matters here, I believe..... but the overall
> setup my end wasn't self-curing fast enough in my opinion....

Now that I know the wait is required, I'm willing to be patient on the rare occasion when it is required. It just threw me when I didn't know what was going on.

The technician I spoke to said you can use the ABB phone app to immediately refresh your session. I have an aversion to such gimmicks, so can't vouch for whether it actually works.

~ Tim

[Darren Wurf]

On Tue., 8 Oct. 2019, 15:09 Gary Pope, <g...@alchester.com.au> wrote:

I'm with AussieBB and they're great so far (since 16th Sept only)...

...

I had to force a WAN request on the pfSense box, in order to get my
static IP properly again,  which is delivered as a dynamic IP,  but
always the same  (for which we pay the $10 fee... which is fine).

For those on AussieBB, who *do not* have the static IP add-on, I suggest the following:

Call support and say you want to

- opt out of carrier grade NAT (requires a reason, e.g. running services or gaming)

- opt into the IPv6 pilot (if you want it)

- request port unblocking (if you want outbound port 25 for example)

Without carrier grade NAT your IP should be relatively stable, from what I've read AussieBB doesn't tend to change it very often. You'll also remove any potential double-NAT issues and gain inbound connectivity. The other two items are optional regardless of whether you're on a static IP or not, I suggest you do it while you've got support on the line anyway as the whole process takes about a minute.

Cheers,

Darren