44net

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3198 discussions

Re: [44net] greylisting on mailman (this list)
by Rob Janssen 11 Oct '17

11 Oct '17

> The problem is that the large email purveyors like AOL, Yahoo, Microsoft, etc, > use large server farms that balance the load between multiple hosts, so > when the mail retries it comes from different IP addresses on every retry. > Microsoft, for example, lists thousands of IP addresses as part of their > email service. > Greylisting by IP address hasn't got a chance of working in that > environment. When I ran my own mailserver I had greylisting that only worked by sender mail address. Additionally, it did the usual SPF checking etc. This did not cause the abovementioned problem, but I'm not sure it added much spam prevention. I had other methods to detect trojaned PCs with bad SMTP senders (e.g. doing PIPELINING without having negotiated it) and that was much more effective. Rob

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Re: [44net] new ntp server for amprnet
by Martinez, Philip 11 Oct '17

11 Oct '17

Hi Ronen, Yes I can make my ntp server available to non amprnet host just let me know the ips its comming from.. I can expect to receive from. host name: kc3ipf-01.ampr.org. Philip KC3IPF >What about the kc3ipf server ? is it available also to non amprnet hosts ? > > >Ronen - 4Z4ZQ

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Re: [44net] new ntp server for amprnet
by Josh 10 Oct '17

10 Oct '17

Thanks Lynwood. Could you change the location of ntp.vk2hff.ampr.org from UK to AU please? Josh VK2HFF -------- Original message -------- From: lleachii--- via 44Net <44net(a)mailman.ampr.org> Date: 11/10/2017 01:54 (GMT+10:00) To: 44net(a)mailman.ampr.org Cc: lleachii(a)aol.com Subject: Re: [44net] new ntp server for amprnet All, I've added the NTP servers in this email thread to the Services Wiki (I didn't include Bigben since that's not on AMPRNet, let me know if you think I should add it, Brian). Also, my NTP server is a Stratum 2 that pulls from various military, industrial, government and educational Stratum 1 servers in North America (including AMPRGW). John, be sure to let us know when you've assigned a 44 IP to your server. For reference, my NTP Server address is: kb3vwg-001.ampr.org (44.60.44.1) 73, - Lynwood KB3VWG _________________________________________ 44Net mailing list 44Net(a)mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net

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Re: [44net] new ntp server for amprnet
by Rob Janssen 10 Oct '17

10 Oct '17

> The Motorola device has no NMEA output, but can produce 2.5, 5, 10, > 12.5, or 25MHz reference frequencies depending on jumper settings inside > the box. > I wish I had a use for them. Right now they're just another piece of > the junk piled up in my garage. I use the NTP-syncronized clocks in > my computers as my primary time reference because they're on all the > time anyway. Not so useful as a time reference but you could use it as a frequency reference for a microwave station, a beacon or a repeater. Rob

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Re: [44net] new ntp server for amprnet
by Rob Janssen 10 Oct '17

10 Oct '17

> In the US, the surplus equipment market occasionally had GPS-trained > oscillators that could provide 10Mhz and 1pps clocking as well as NMEA > output. They were parts of CDMA cellphone base stations, each of which > had at least two. The one I have was made by HP. I also have one that > is a Motorola device that was used to synchronize simulcast transmitters > in repeaters. That is the kind of box (from other manufacturers) that we use as well, attached to a PC with 1PPS and NMEA and to the repeater with 10 MHz. Chrony on the PC keeps the Linux clock within 10us (usually within 1-2us) which we require for the simulcast, and 10 MHz provides the exact transmit frequency reference. Power... well, maybe it has an oven stabilized crystal oscillator. Or very old digital logic that is a bit too power-hungry. Of course a lowcost uBlox/ SiRF module is easy to get going and provide 1PPS for ntpd. The LeoNTP box is a plugin-and-forget network clock, of course not the cheapest solution. A Raspberry Pi can be used, I have one in the IPv6 NTP pool at 2a00:f10:103:201:ba27:ebff:fefd:984 Rob

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Re: [44net] new ntp server for amprnet
by Rob Janssen 10 Oct '17

10 Oct '17

> I also have a stratum 1 NTP server, it is on 44.13.151.3 (ntp.g1fef.ampr.org) and it is open to 44/8 > It’s a Symmetricom S200 with Rubidium clock and GPS and is located in the UK for anyone in Europe it would be better choice than the US based clocks. For people who want an easy stratum 1 server and don't have money for such gear, have a look at the LeoNTP. It is made by a UK radio amateur and it is a GPS locked NTP server in a very small package. It costs "only" 300 pounds (about $400). We have considered it for repeaters but unfortunately it cannot provide 10 MHz and 1PPS at the same time, which we do require. Rob

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new ntp server for amprnet
by Martinez, Philip 10 Oct '17

10 Oct '17

Hi team, My name is is Philip (KC3IPF) and I'm making my network ntp server available to the amprnet. All I ask is pre-notification of the subnets being served so I can open my firewalls and permit the ntp daemon to service the networks. You can contact me pm1183 at messiah dot edu. It is a stratum 3 server and all I ask is don't be abusive. The address is kc3ipf-01.ampr.org. Philip

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OT: Toy measurement equipment
by Rob Janssen 10 Oct '17

10 Oct '17

I remember well from when I started in electronics how much money had to be spent on measurement equipment, e.g. a multimeter or a scope. Today, there are some very interesting devices available from Chinese suppliers e.g. via Aliexpress or Ebay. Can be very useful for quick measurements/testing in the amateur radio station, to get new (young) people interested in electronics, etc. For about $25 you can get the Aneng AN-8008 DMM that has 4 digits (9999 count) and measures DC and AC (true RMS!) voltage and current, resistance, capacitance, frequency and can even generate audio tones. It has very low ranges, the least significant digit displays uV or uA on the lowest range. Very useful, as long as you don't use it to measure dangerous voltages or currents. I also got a kit for a 200kHz (1 MSPS) single-channel storage scope for less than $25. Takes about 2hrs to assemble, and you have a pocket size storage scope that I would really have liked to have back in the days of packet radio, you can have one of them connected to each receiver and see the audio quality all the time. It can display peak and RMS voltage, frequency etc on-screen. JYE TECH Digital Oscilloscope DIY Kit (can be found with or without case) Another nice toy is the M328 LCR-T4 component tester. Based on a design originally published in a magazine, there are several different versions available that differ in connections and if it does/does not include a case. I have one that uses a ZIF socket for the connection. It has 3 test terminals and you can connect a transistor, fet, triac, resistor, capacitor, inductor, diode, zener etc to the test terminals and it will display the type of component, pinout, and value on the LCD screen. Includes other useful info like the ESR of a capacitor, capacitance of a diode, etc. Can be found for less than $10. Of course it all isn't professional test equipment, but it is a lot of fun for the money if you ask me... Rob

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Re: [44net] new ntp server for amprnet
by Rob Janssen 09 Oct '17

09 Oct '17

> Now it's back.. >http://wiki.ampr.org/wiki/Services The server gw-44-137.pi9noz.ampr.org (44.137.0.1) mentioned on that page is also still available to AMPRnet users, but of course it is in Europe (Amsterdam) so not as accurate for users in the USA as a more local server would be. It has about 150 clients. The server itself is usually within 300us of UTC, it is referenced from 8 GPS clocks of different types (Datum 9390-52054, Trimble Thunderbolt, Meinberg) used in our same-frequency repeater network, plus various other external sources. It automatically fetches the leap-second announcement file from IERS once a month to handle leap seconds smoothly. Rob

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IPv6 stuff
by Steve L 08 Oct '17

08 Oct '17

I added a collection of notes I have had locally on IPv6 to the wiki. I am not much of a wiki guy, so I encourage others to edit its layout and make it look pretty. But its a start to put the info in one place. And others can add to it as we progress. http://wiki.ampr.org/wiki/Ipv6 Brian/Chris: Also, is there any chance it could be changed so that PDF's could be uploaded to the wiki? Looks like it only accepts images presently. Steve, KB9MWR

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