Wednesday, May 24, 2017

Paradise ponders: routers, sprinklers, and ARP proxies edition...

Paradise ponders: routers, sprinklers, and ARP proxies edition...  It was a long, long day for me yesterday.  The end result of yesterday's work (and some more this morning) is at right: the Internet speed test on my office laptop.  That's what I get when I send a gigabit stream of Internet data through two routers and a radio link to my laptop.  It actually varies from around 500 to 800 mbps, and 800 mbps is the limit of what my laptop's network interface can do.  Woo hoo!  I got data now!

Yesterday I ripped out our two older MikroTik routers and replaced them with newer, (much) faster models (RB/1100AHX2).  I brought up the one in my barn office first.  That was a tedious, but fairly straightforward affair, and by 1 pm I had that up and running.  After returning from a very pleasant lunch with Debbie and our friend Michelle H., I started on the house side.  I had it all installed by 6pm, and it was talking between the house and the barn just fine (over my new radio link).  But it wouldn't connect to the Internet at all.

I troubleshot it for three hours, with (to me!) very puzzling symptoms.  The new MikroTik router could talk to the cable modem just fine, but nothing connected to the router could do so.  Sounds like a routing problem, right?  I inspected and re-inspected all the address and routing configuration, and found no problems at all.  No reason for it not to work!  So then I did some packet sniffing, using a constantly-running ping session on Debbie's workstation as a source of known data.  The outbound ping got routed to the cable modem just fine, but then the cable modem never responded.  Tried the same thing with a ping from the router, and the cable modem responded just fine.  My tired brain couldn't process that information, so I went to bed and hoped that with fresh, caffeinated neurons in the morning I could figure it out.

Round about 2 am I woke up, visions of router configurations dancing in my head.  After thinking about it some more, it occurred to me that it might be a problem with ARP (the Address Resolution Protocol).  Unless you're a networking geek, you probably have no idea what that is.  In technical terms, it gives networked devices a way to translate an IP address into an Ethernet destination (a MAC address).  This isn't a great analogy, but it's a bit like a service that translates ZIP+4 codes into a street address.  In terms of my problem, if the router was trying to send a packet to an IP address (in this case, Debbie's terminal) that it didn't know the corresponding MAC address for, it would broadcast an ARP request to all the devices directly connected to the modem, and then my new router should reply (because it already knows how to send something to that IP address).  If that ARP request was never sent, or if my new router never replied to it, the symptoms would match what I was seeing.

So I got up around 3 am and started working on the problem.  With a bit more packet sniffing, I was able to determine that the cable modem was sending an ARP request – but my new router never responded.  At last, something concrete to track down!  With a bit of poring through documentation and configuration screens, I found the place where ARP behavior is configured.  That ARP setting on the screen at right is ordinarily set to “enabled”, but on this particular interface (the one connected to the cable modem) it needs to be set for “proxy-arp”.  Why?  My router's ether1 interface is connected to the cable modem, and it's address is 10.0.0.2/8.  All the other router interfaces are subnets of that one.  For instance, the client machines are on 10.1.4.x/24.  That matters because all the IP addresses that the router issued ARP requests for are within 10.0.0.0/8 – so my new router didn't know that it had to reply; for all it knew some other device would reply.  By changing that setting to proxy-arp, the router sent the ARP request to the interface with a matching subnet, and that interface replied to the ARP request.  With one simple little tweak, all of a sudden the entire network on the house side started working correctly.

Amazing what a little sleep will do for your troubleshooting capability!

We had another little milestone yesterday: Mark T., the fellow installing our new lawn sprinklers, arrived and started digging the trenches.  Progress!  His trenching machine is working much better now that our soil has dried out a bit. :)  He's starting on the section of our yard that we call the “driving range” (because that's what the previous owner did with it).  It's about half our total grass area.  He thinks he'll be finished trenching that part by Friday...

Monday, May 22, 2017

Paradise ponders: antennas, lunch, and seromas edition...

Paradise ponders: antennas, lunch, and seromas edition...  I worked all day yesterday (and most of the day today) getting my new 1.4 gbps backhaul link installed, configured, aligned, and tested.  And it works!  I've got a solid gigabit connection between the house and my office in the barn.  Unfortunately my existing routers are limiting my use of this, along with the network interface on my laptop.  My new routers arrived today, a day early, so tomorrow I'll be configuring them.  That should get my laptop up to about 250 mbps, the limit of its network interface.  Next time I get a computer (likely sometime next year when Apple releases the updated Mac Pros), it's network interface should handle the whole gigabit stream.  Woo hoo!

Debbie made us a fantastic lunch yesterday.  Simple, but oh-so-good.  Broiled asparagus, a baked potato with butter, sour cream, and chives, and half of a prime ribeye steak.  It still blows me away that we can get prime beef at the butcher counter of our local grocery store – that stuff was next to impossible to get in San Diego unless you went to one of the outrageously expensive fancy beef stores, where that ribeye might set you back $50 or $60.  Here they're a modest premium over choice – but oh so much tastier!  The best part of that meal, though, was the asparagus.  Debbie broiled it after tossing with some olive oil, pepper, and some other spices.  Yum!

This afternoon we had to take Cabo back to the vet to get her seroma drained again.  Once again, no charge.  Poor little girl is filling up with fluid near her spay suture.  This time the vet told us to just let it fill up and don't worry about it – in a week or two it will be reabsorbed.  If Cabo could have understood that, she'd have been very happy to hear it – she doesn't like the vet's office one little bit.

Saturday, May 20, 2017

Paradise ponders: antennas, voles, and seromas edition...

Paradise ponders: antennas, voles, and seromas edition...  Today I continued working on my antenna project.  The antenna on our house is completely installed except for aiming (which I can't do until both antennas are up) and painting (which I can't do until I've aimed it).  Fishing the cable through the wall of Debbie's office was a two-person job, and Debbie has recovered enough that she could lay down on the floor and do the indoor part of it while I crawled out on the roof to do the outdoor part.  Progress!  The antenna is wired up to its POE injector, ready for connection to the new routers I've ordered; it's management WiFi network is on the air.  I also started on the barn antenna, but around 4 pm today I just sort of conked out.  Lack of sleep last night caught up with me, I think...

It was such a gorgeous day this morning that I decided to go for a walk, taking Cabo with me.  The skies over our heads were perfectly clear, but there were puffy clouds over the mountains to both the east and west of us.  With snow on the peaks and the valleys a beautiful green, flowers popping out, and all our summer animals and birds back, it was a real treat for me.  I took Cabo along for the walk, and she had herself a grand adventure.  On one of her forays into the tall alfalfa (like in the first photo), she caught the scent of a vole – and then flushed it.  That triggered an instinctive reaction to pounce on it, which she did – and she caught it.  She raised her head, with her jaws holding a struggling vole, and then calmly crunched it, killing it.  Then she dropped it and looked at me as if to say “Now what do I do with this?”  She showed no inclination to eat it, which is what Mo'i or Race would have done before I got a word out.  But she definitely wanted to find more voles – for the entire remainder of our walk, searching for voles is all she wanted to do!


The second photo is of a stand of mustard, backlit by the morning sun, with some dew still on it.  Even mustard can be pretty! :)  The last photo is the distance view to my west as we were walking.  Pretty as a postcard, isn't it?

We took Cabo to the vet yesterday so the vet could take a look at a seroma that we'd noticed at the site of her spaying incision.  The vet (Dr. Watkins) was quite surprised – said he doesn't often see a seroma on a simple spay, and he was worried that it might mean the incision on the body wall (not the skin) had herniated.  He palpated it and found nothing suspicious, then took multiple X-rays and also saw nothing.  These seromas do occasionally happen for unknown reasons, they're not dangerous, and generally they go away on their own as the body reabsorbs the fluids.  So he just drained the fluid that had already accumulated (about 20cc, or a tenth of a cup), gave her a shot of antibiotics, just as a precaution, and sent us home.  We're to watch for further accumulation and bring her in for draining as required, but otherwise we're just waiting for it to go away on its own.  The vet wouldn't accept any payment for any of the work he did yesterday, saying it's part and parcel of the spay.  A nice gesture, that was.  We'd have happily paid for it, because (so far as we know) it wasn't the vet's fault that Cabo got a seroma.  But to have such great service, delivered as if we were close friends, and then say it's free – well, that can't help but put a smile on our faces...

Friday, May 19, 2017

Paradise ponders: drones, antennas, and remembrance...

Paradise ponders: drones, antennas, and remembrance...  Today would have been my dad's 93rd birthday, were he still alive.  Debbie and I were out to dinner with friends (Gary and Elayne S.) last night, and on our drive dad came up in the conversation.  We were passing by some plants we didn't recognize, and Debbie commented that my dad would have known what every one of them was, whether it was native, what it's natural history was, etc.  And that led us into a conversation about my dad with our friends.  We miss you, Pater...

The contractor installing our sprinklers is working with a sub-contractor to map out the sprinkler head locations (there are just over 200 of them!) in a software app so he can price out our project.  It turns out that the county maps the app depends on are obsolete for our purposes (mainly because the irrigation canal was rerouted since the maps were last updated.  So our primary contractor engaged a fellow to take aerial photos of our place from a drone.  This fellow showed up around 10 am with his Phantom drone, zoomed it up to 700' high, and then got nice aerial shots.  The entire process took about 5 minutes.  He flew it from an iPad strapped into a controller, and it sure looked easy to do.  I don't have the results yet, but I'll post them when I do...

In between all the other goings-on, I installed the first (of two) antenna for the data link I'm putting up between our house and barn (where my office is).  I started with the house, which is the “master” of the pair.  The only part of the installation I've finished so far is the mechanical mount, which actually was very straightforward.  My little oscillating saw (at right) made cutting those holes through the siding for the mount's five feet easy. The first photo below is what the mount looked like after I installed it.  The actual antenna mounts to the gold colored mast, as you can see in the second photo.  The last photo just shows how high up that thing is.  I was at the very limit of what I could safely do on that ladder!


I'll be caulking all the wood I cut through to make it waterproof, then painting all that silver and gold colored stuff white.  I also have to install a ground wire, which will have a rather convoluted route in order to keep from traversing the steel roof.  Then comes likely the most difficult part of installation: getting the outdoor Ethernet cable through the house wall, without causing a leak, or a place for animals or insects to get in.  Part of this will involve snaking the cable through the wall of Debbie's office, where I'm not allowed to do anything ugly. :)

One consequence of installing gigabit Internet access that I didn't anticipate is that my existing routers can't keep up with the Internet feed.  It would be just plain silly to have gigabit Internet if I can't get that capacity to our devices, so I'm also going to have to upgrade our routers.  I'm using MikroTik routers, which I just love (so much easier to manage than Cisco routers!).  The one I chose has 13 gigabit ports, with 2 gbps overall throughput.  That's enough performance to do the job nicely, and enough ports that I can have a dedicated port for all of our computers – which means we'll avoid bottlenecking our switches (and I can keep those!).

Wednesday, May 17, 2017

Paradise ponders: snow and marbles edition...

Paradise ponders: snow and marbles edition...  When I woke up this morning and looked out my window, here's what I saw:


Yup, that's right.  A winter wonderland.  The dogs were quite enthused about this!  I was ... less so.  At least the asphalt in our driveway stayed warm enough to melt the white stuff.  If this global warming warms things up any more, we'll be frozen solid!  Almost every day in these part we're breaking 100 year records for cold and wet – exactly the opposite of what those infallible climate models predicted we'd see in this decade.  Sheesh...

When my father was a toddler, in the late 1920s, he had a favorite toy: a set of wooden ramps down which marbles would roll.  I didn't know that in the late 1950s when I played with this same toy at his parents' (my grandparents') house.  I remember thinking it was a big, heavy thing – when my grandmother sent me to the closet she kept it in so I could get it out and play with it.  It seems small and light to me now. :)  I also remember the marbles as great big taws (shooters), but actually they're just ducks.  It's made very simply, and not particularly well-finished, though in my memory it was a finely crafted and polished wood.  No matter, the memories are the important part.  It is made of a fine-grained hardwood (maple at a guess). 

I found out that it was my dad's toy on one of our many trips together.  It was during a far-ranging conversation about his life before WWII, the same conversation in which I learned that his pre-war career plan was to become a chicken farmer.  In another part of that conversation, he was telling me what it was like to have grown up in the Great Depression.  At the time of the stock market crash, he was just five years old.  This toy was one of the few that he had at that time, and there was no money for other toys until he was too old to want them any more.  Most of the toys he remembered were things that his father clapped together, or that he made do with.  Hoops from a broken basket and a nice stick, for instance, made one of his favorites.  But this toy, the marble ramps, was one that he especially cherished because it was one of the few “real” toys he ever had – and it was a gift for him, from his parents, not a hand-me-down from his two older brothers.

I have very few artifacts that belonged to my father, other than documents and photos.  This is the only one I have from his childhood.  I shall cherish it...