My Gorram Frakking Blog

Comcast is Arbitrarily Blocking Port 25

I woke up this morning to find that Comcast had blocked outgoing connections on port 25 (SMTP). Their online information suggests changing to port 587, but this assumes one is using Comcast’s SMTP server, which I am not (I run my own mailserver on hardware I own at a colocation facility).

So I enter an online chat with Comcast technical support, and I am told that once I have been blocked, it is impossible to be unblocked. I am told the same thing by the second-tier support person. They refuse to escalate my request any further. They tell me to switch to port 587.

So I contact the California Public Utilities Commission, only to find out that cable service is not under their jurisdiction. They suggest I look on my Comcast statement for a number to call. Sure enough, buried in the middle of the bill, is a cryptic line with contact information in my city.

I call the number, and a very nice lady from the city supervisor’s office answers. She tells me that they only regulate Comcast cable TV, and not broadband, but she puts in a call to her Comcast government representative (Cynthia Gomez), who calls me back a little while later.

Ms. Gomez gives me the number to Comcast’s “Customer Security Assurance,” 856 317-7272. There, Edgar tells me he can remove the port 25 block, but that I should switch to port 587, and that if I am blocked again, it will not be removed. He also suggests that I check SenderScore where I can see that my IP address has been placed on a couple of blacklists, including SORBS and 510 Software Group.

It is interesting to note that they’re treating my IP address as if it were statically assigned.

I don’t use Windows, but I’m wondering if my wireless network has been compromised.

Problems

The problem with changing port numbers is that it is, at best, a temporary solution. Especially for an ISP like Comcast, with millions of subscribers, it won’t be long before the spammers determine what the new port number is (it is readily available on Comcast’s website).

The Comcast CSA tech referred me to SenderScore. SenderScore claims they have not seen enough email from my IP address to make a determination, but shows that my address is on two blacklists. According to 510 Software Group,

IP address 24.4.xxx.yyy is listed here as 24.4.79.222.comcast.net misc.spam.

If you are not running a mail server on 24.4.xxx.yyy, this listing should not affect you in any way, and you should ignore whatever source told you that this might be a problem.

The misc.spam group is mostly (but not entirely) composed of entire addresses blocks that have a) sent spam here, b) have consecutive or missing reverse dns, and c) have no customer sub-delegation via either the controlling RIR (ARIN, RIPE, LACNIC, APNIC, etc) or an rwhois server referenced in the main RIR records.

In particular, 24.4.xxx.yyy has reverse dns of c-24-4-xxx-yyy.hsd1.ca.comcast.net. Since your domain name does not appear as the last components in any of those reverse dns names, that needs to be fixed first. Any email sent to the address at the top of this page will be ignored until that is fixed.

In my opinion, the following comment also applies to static ip addresses, where the provider does not actually identify the user of that ip address by domain name.

So, it appears that Comcast is using external blacklists to determine if I should be blocked, but I’m on the blacklist because of Comcast’s own misconfiguration.

More news as events warrant.

Image Upload Utility Idea

A quick entry to record an idea I had for a useful utility. A droplet application that takes the images dropped, makes a set of thumbnails, and uploads them and the originals to a server, and then puts markup on the clipboard.

It could be enhanced to pop up menus for frequent destinations, and image sizes. It could even pop up a crop editor, which could provide constraints for common aspect ratios/sizes/widths/heights. These could be set by destination.

University Satellite Delfi-C3 Successfully Deployed

The Delft University of Technology in the Netherlands successfully launched and deployed a 3U Cubesat called “Delfi-C3”, into polar low-Earth orbit. Because it carries no batteries, it only operates when not in eclipse. We on the West coast of the United States, and those in Alaska, were the first ones able to hear it. I was unable to hear it on its first pass at around 0455 UTC (2155 local), but they encouraged me to try again for the second pass, at around 0631 UTC. I finally heard it at 06:39:08 (give or take a second or two). (Pictures of the satellite.)

I had almost given up, when I remembered to try the backup frequency, and voilà! There it was! I was able record audio (received by an ICOM IC-R1500 connected to my Mac via USB, recording into QuickTime Player at the device-native format) and send it to the team.

…

And I just got off the phone with Wouter! He called me to thank me for sending them the audio file, and to tell me that it was, in fact, Delfi-C3, and that I am the first person to hear it. He says this confirms that it is operating in Science mode on the backup frequency. Sadly, it appears that my recording was too noisy to allow any telemetry to be decoded.

What a rush! I’m so thrilled for those guys, and thrilled to have suddenly been a real, if small, part. Wouter tells me they are all very happy to hear that their satellite is alive and well.

Congrats, guys!

iPhotos of Saturn

I snapped these by holding my iPhone, with its crummy, scratched-up lens, up to the eyepiece of my little telescope. The cold wind was shaking the scope and making me shiver. The actual view was much better, but I was surprised enough to get these that I decided to post them here.

I tried with my digicam, but gave up too soon; I couldn’t get it to show up at all.

My first amateur radio contact ever, with Astronaut Dan Tani aboard the International Space Station

On February 6, 2008, I had the great honor of making radio contact with Astronaut Daniel Tani, as he flew overhead aboard the International Space Station (ISS). This was one of the most exciting and awesomely cool things I’ve ever gotten to do. It was my first voice ham radio contact ever, and after a great deal of help from the tireless Kenneth Ransom, Dan and I finally managed to schedule a time to chat.

Today I received permission to post publicly a photo, taken by Cosmonaut Yuri Malenchenko, of Dan while he was talking to me:

Almost as cool was the email I got from space when I was first trying to schedule the contact with Dan. It was a bit of a challenge, because you need line-of-sight in order to establish radio communications at the frequencies we were using (144 MHz, also known as 2 meter). This means that the contact has to occur during a pass. Since ISS orbits the Earth once every 90 minutes, and the Earth itself rotates during that time, it’s only overhead during certain times of the day, and those times are different every day.

Add to that the fact that Dan is an incredibly busy person up there, so we had to find a time when he was both off duty and ISS was in sight. Around 1600 PST on February 6th that finally happened (I think Dan stayed up late to make it happen, and for that I thank him). We were able to chat for about 9 minutes, and it was great fun.

Thanks again to Kenneth Ransom, Yuri Malenchenko, and Mike Kobb (who assisted on the ground as my antenna tracker).

I had the privilege to go to Florida to see Dan’s first shuttle mission launch (STS-108). I lack the words to express my extreme appreciation of Dan, for making that possible, and for taking the time to do this with me. From the bottom of my heart, thank you, Dan!

Solar Thingie

I came across a page about peak-power tracking in solar PV applications. I decided I wanted to goof around with solar stuff, so I started tinkering. This is what I have so far:

So far there’s not much going on. It measures voltage generated by the panel, and current being delivered to the load (a little red LED in this picture; the circuit is powered from a bench supply). I started adding a 5-volt LDO, which I’ll use to regulate power to the MCU and LCD when powered from the panel.

If I can get AVaRICE to stop hosing my ATmega324P parts, I’ll slow this down to 4 MHz (it’s running at 16 MHz here) and power it from 3.3 V. That should work better in actual sun-powered applications.