TIL: How to disable SLAAC-assigned IPv6 address and assign my own

This is one in an occasional series of notes to future me, and possibly others who might find it useful.

Last week, for no apparent reason, I started getting “403 Forbidden” errors when using the TripIt API from my Linode system. I hadn’t made any changes to the code or the system; it just started happening. I was able to use the exact same code from my machines at home, so I suspected some sort of network issue.

Today, I tried to figure out what was going on. Creating a new Linode and running the code there didn’t help – I still got the errors.

I stumbled across a question on the Linode forums that was vaguely similar to my situation; it turned out that Google had blacklisted the Linode /64 network in Frankfurt (where the questioner’s Linode was located). The questioner could use the service if they forced the connection to go over IPv4, so I tried that.

Sure enough, I could get to the API if I forced the use of IPv4 (I tested with curl), but that wasn’t a real fix.

Linode had suggested that the questioner assign themself another /64 block and use that, but didn’t go into any detail about how to do that. Here’s how you do it (on Ubuntu 22.04).

Step 1: Use the Linode Cloud Manager to add a /64 block to my instance (click on the Linode name, click on “Network”, then “Add IP Address”)

Step 2: Reconfigure the network on the Linode to use the new block and NOT use the SLAAC auto-assigned address. This turned out to be difficult, because I couldn’t find an example. After far too much searching, I eventually found the proper documentation for the network manager configuration piece that I had to modify, etc/systemd/network/05-eth0.network.

I had to remove the IPv6AcceptRA=true line in the [Network] section, add an Address line for the address I’d chosen in my new /64 block, and add an [IPv6AcceptRA] section with a UseAutonomousPrefix=false line. The file now looks like this:


[Match]
Name=eth0

[Network]
DHCP=no
DNS=45.33.58.84 173.255.212.5 173.255.219.5

Domains=members.linode.com
IPv6PrivacyExtensions=false

Gateway=45.33.34.1
Address=45.33.34.52/24

# Force my own ipv6 address
Address=2600:3c01:e000:9c0::2/128

[IPv6AcceptRA]
UseAutonomousPrefix=false

I rebooted, and all is well; my SLAAC address is gone and the TripIt API works again!

Morning Moon

I caught a glimpse of the waning crescent moon just as the sky was beginning to brighten this morning, and it was the start of a very pleasant day.

waning crescent moon seen through intersecting telephone lines in a dimly lit sky

A pleasant day, but not terribly noteworthy, though we did have an enjoyable walk through Los Gatos with the Shir Hadash Walking Group, a couple of tasty home-cooked meals, and an evening walk to the ATM to make sure Diane and I both met our exercise goals for the day, something which didn’t happen every day on our recent trip.

Quiet days are nice.

Thank God we’re on 19th Avenue!

We left Ferndale about 10:30 after another nice night at the Gingerbread Mansion and a nice conversation at breakfast.

We were in a bit of a hurry by the time we left – friends in Palo Alto had invited us to a pool and dinner party which started, as usual, at 3pm. We normally don’t get to their house for these parties until 5 or so, and I had hopes that we’d make it by then.

But we didn’t want to leave Humboldt County without seeing a few giant redwoods! Tammy, who’d greeted us at the Humboldt Botanical Garden yesterday, had suggested we stop at the Rockefeller Forest instead of driving down the Avenue of the Giants, so we followed her advice and enjoyed a few minutes communing with nature without any other tourists around.

A woman and a man standing in front of a giant redwood tree in the middle of a forest

We didn’t have time to explore, though, so we returned to Highway 101 and headed for our first charging stop of the day at the One Log House a few miles south of Garberville. The house is a tourist attraction which has been around for decades – there used to be a gift shop there and you could pay a couple of bucks to get into the house itself. But new owners had turned the gift shop into a pot dispensary…which went out of business recently! Fortunately, the EV charging station was still operational, and there was a gas station across the street with a convenience store and restrooms.

A woman standing in front the door to "One Log House"

It was smooth sailing on 101; we’d found a promising Thai restaurant on Yelp just north of Ukiah, but when we got there, it had a “Opening Soon” sign (making me wonder about the reviews). There was a casino with a restaurant that got good reviews nearby, so we drove over there, only to find that the restaurant was closed until dinner; they did have a fast food counter, but nothing appealed. We finally ate at Ukiah Thai Cuisine in downtown Ukiah – it was quite pleasant, and I’d go back.

But all of the false starts had put us well behind schedule, and we were barely halfway through the trip. We made good time to the charging station at the Safeway in Healdsburg, only to find that the charger wouldn’t accept my Electrify America pass or their app. I called their customer service – it took two tries to reach a human, who was able to get the charger to start…after another ten minutes or so. At least we left with a full battery and no need to charge again until we got home!

Traffic moved really fast on 101 from Healdsburg on, and I was hopeful of making the party at our usual time…until we got to the Golden Gate Bridge. I was in the right lane, which was a bad decision – there were a lot of people merging into that lane, so we were stop-and-go while the other lanes moved along smoothly. Once we were on the bridge, we moved well – but once we left the bridge and got onto CA 1, things stopped again. It took about 25 minutes to get through the Presidio, Park Presidio, and Crossover Drive before we reached 19th Avenue and traffic started flowing well again – something I’m not used to seeing on 19th Avenue.

We finally reached our friends’ house at 6:30; the pool was closed, but there was still plenty of food, wine, and good conversation, so it was worth the trek.

Eureka and Ferndale – mostly gardens

We had hoped to visit Humboldt Botanical Garden yesterday on our way to Ferndale from Ashland, but the trip took longer than I’d expected, so we would have been lucky to get there before the last entrance for the day. We decided it’d be smarter to wait and go there today – and we were right. We spent a little over three hours in the garden and could have spent longer if we’d brought lunch.

The garden is on the campus of the College of the Redwoods, a two-year private college that specializes in career education; in fact, the road leading to the garden warns drivers that trucks have the right of way and cars might have to back up to let them through…and you’d better believe it, because the people driving them are learning how as part of their degree program! Fortunately, we were there at a quiet time for the driving school.

We began our exploration in the formal gardens, near the entrance.

A bee atop a yellow flower, with other yellow flowers and foliage in the background.
Rudbeckia Fulgida – Goldsturm
Rosa – Knockout
Astroemeria – The Third Harmonic
Bidens ferulifolia – Beedance Painted Red
Red Dianthus
Romneya coulteria – Matilija poppy
Lewisia cotlyedon – Siskiyou lewisia
Landscape with Cows and Greenhouse
Dahlias
Dahlia with pollinator
Inula (I think)

One of the highlights of the garden is “All Happy Now”, an earth sculpture which is a cross between a ziggurat and a labyrinth. It’s about a mile from the entrance (depending on which paths you take to get there and back), and the walk in the sculpture is another half a mile. The weather was perfect – cool and not too sunny.

“All Happy Now” Earth Sculpture
Atop “All Happy Now”

We climbed up to the Oliver Eitzen Lookout Point on our way back to the entrance so we could get a good view of Humboldt Bay.

Humboldt Bay

One of the highlights of the Garden is the Lost Coast Brewery Native Plant Garden, so we thought it only appropriate to visit the Lost Coast Brewery & Café in downtown Eureka for lunch. We didn’t see any plants there, but did enjoy the food and beer.

We also visited Dick Taylor Chocolate; we could have taken their weekly factory tour if only we’d spent two hours less in the Garden. Maybe next time.

We left downtown Eureka and charged the car at Bayshore Mall, then returned to Ferndale and the Gingerbread Mansion in time for wine and goodies. Then we walked back into Ferndale to work up an appetite for dinner, starting with another quick visit to the Ferndale Cemetery.

We walked up to Main Street and then towards the Ferndale Bridge (well, as far as Town Hall). On our way, we stumbled onto Hadley Gardens, a quirky garden devoted to native plants and wildlife, with a side order of solar power (there’s a Tesla Powerwall in the hobbits’ toolshed in the photo below).

We went back to Ferndale Pizza Company for a light dinner – we split a personal pizza!

Tomorrow, we leave Ferndale for home.

It could have been worse

Diane and I went to the Legion of Honor today to see their current exhibition, Japanese Prints in Transition.

There was a pickup truck overloaded with stuff ahead of me on the Highway 17 on-ramp. I stayed far behind it on the ramp, and wasn’t surprised when pieces of cardboard and other junk started blowing off it when it accelerated at the end of the ramp. I was able to stop without anything hitting me (including the cars behind me!); the truck pulled off to the side, and I drove on; all was well. Or so I thought.

We’d been to the Hagi Uragami Museum last month in Japan; it has a room devoted to ukiyo-e (floating world woodblock) prints, but it was closed on the day we visited. We made up for it today at the Legion; there were six rooms of woodblock prints. There was even one room of woodblock erotica!

We wanted to get out of the city before rush hour, so we skipped the rest of the museum and headed to the car to drive home.

We didn’t get very far, though, before the dashboard went “beep” and said that my front left tire was dangerously low – 19psi. I guess I hadn’t completely avoided the debris from the truck after all!

I found a nearby gas station with, wonder of wonders, a free air pump, and filled the tire. But I could only get it up to 30psi and it started to go down again, so we got off the highway and went to Wheel Works in Daly City. They were too busy to fix or replace the tire, but they did pump it up to 45psi so I could get back to Los Gatos even with the leak. By the time I got to Wheel Works in Los Gatos, the pressure was down to about 35psi. They said they’d be able to take care of the tire in the morning, so I left the car with them and we walked the mile-and-a-half home.

I guess I should have given that truck even more room!