44net February 2016

44net@mailman.ampr.org

71 participants
82 discussions

Re: [44net] DNS cleanup
by Rob Janssen 07 Feb '16

07 Feb '16

> Rob, if you'll tell me which subnet that has "children" should be removed > and which of those "children" should be kept, I'll make a note of the > "children", delete them, delete the erroneous subnet, and add the > "children" back in. Annoying, but it should take only a few minutes, > less time and more productive than arguing about it on the mailing list. It is the 44.137.24.0/22 subnet as I mentioned before. But be careful: those children are IPIP gateways and have that subnet registered in their gateway system. I'm sure when you delete them through the UI, the subnet will be deleted from their gateway as well. That is not good. I wonder what the database structure is and if you could maybe just delete the record from the database without affecting the children. When there are all kinds of pointers back and forth between parent and child records, that would be something that needs to be fixed. It should be easy to add and delete subnet levels between existing ones, e.g. a new regional subnet between a country subnet and users. We are re-arranging things all the time as the network develops. Probably the subnets should just be stored neutrally, and the parent/child relationship should only be established at the time the records are retrieved for display. And deleting a subnet should not infer deleting everything that is in it, the contents should just be promoted to the next higher level. Rob

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Re: [44net] DNS cleanup
by Rob Janssen 07 Feb '16

07 Feb '16

> Were there multiple entries for 44.137.24.0/22 ? > I still have it in my allocation list. the whole subnet was in use for > the regional local access point I was co-sysop for. That access point is > not operational at the moment, but I would like to keep that allocation > for when it comes back in the future. It is precisely this flexibility that is missing in the portal. There is no way to insert or delete regional subnets when there already are user subnets registered below that level. And there is no way to resize a subnet or transfer ownership either. I would like to register all regional subnets for clarity of the allocation tree, and transfer them to the proper user when that is appropriate. This can be done in HamnetDB and there I have registered those subnets to make the structure of the network visible to anyone, but the portal cannot do that. This particular subnet has been planned to be used by the soon to be deployed access point at the Eindhoven UHF repeater site which will route it using BGP via radio link to PE1RDP. So I prefer to delete this entry for now, to clean the allocation list. Rob

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NTP Server Test
by lleachii＠aol.com 05 Feb '16

05 Feb '16

All, I have an NTP Server online at kb3vwg-001.ampr.org. Let me know if it's reachable from your hosts. This is currently in testing (the domain may move perhaps to tick.ampr.org.). 73, KB3VWG

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OpenWRT Security Notice
by lleachii＠aol.com 03 Feb '16

03 Feb '16

All, I've noticed that if someone performs a traceroute to a 44net address routed via an IPIP tunnel on OpenWRT versions 14 or 15 (tested) results in the router giving the Public, Commercial IP address of the device instead of a 44net IP on tunl0, or any assigned forwarded interface. Without intricate detail, this is by design of the Operating System, as the kernel re-packets an ICMP TTL Exceeded, and seems not to connect that new pack as RELATED to the Received Packet in which the TTL had Exceeded. This is fine when all local IPs are Private IPs, or should be forwarded via the Kernel's Gateway; but as they are not, and the only gateway the kernel knows is the physical WAN. The ICMP TTL Exceeded Packet is given the Kernel's source address (with Gateway), and sent hence - a leaked TTL Exceeded packet. Reason: the least computationally difficult method to protect our gateways from rogue packets is to not publicize/announce our Public WAN-facing IP address. In order to prevent this, a RAW Packet Filter rule for all packets received via tunl0 < 2 can be created, preventing processing of TTL exceeded packets for non-44net IPs: iptables -t raw -I PREROUTING -i tunl0 -m ttl --ttl-lt 2 -j DROP iptables -t raw -I PREROUTING -s 44.0.0.0/8 -d 44.xxx.xxx.xxx/xx -i tunl0 -m ttl --ttl-lt 2 -j ACCEPT Those using OpenWRT, please test and confirm issue and its fix. 73, -Lynwood KB3VWG

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Re: [44net] OpenWRT Security Notice
by Rob Janssen 03 Feb '16

03 Feb '16

The main problem with spoofing of course is not that it "attacks" our systems, but that our systems are being hit by backscatter from others that are being attacked, or that we attack others when we are used as reflectors. So be careful to have the right filters so you don't send too much traffic "back" to senders with spoofed addresses. It is correct that you need to allow protocol 4 only on the external network card and NOT on the tunl0 interface. If you do, you allow tunnel-within-tunnel packets, and they could be malicious, but in any case they are incorrect. In the past we have sometimes seen encap loops where some incorrectly configured system kept putting packets into another encap layer and forward them, and this kind of looping can easily be stopped by not allowing protocol 4 over protocol 4. There is an additonal filter that you can make, and which I explained earlier on the list. With Marius' ampr-ripd you can call an external script when the encap route table is changed, and in this script you can maintain an address list of valid IPIP peers, and use that in the firewall to accept IPIP packets only from peers that are announced by the RIP daemon. This will guard you against funny IPIP packets sent by random hackers. Of course it is not sufficient against the determined people, because they can spoof the IPIP packet to come from one of the gateways in the list, and it will be accepted anyway. Blocking "non-44 source addresses on tunnel interface" of course is only possible when you do not want to communicate between net-44 and the rest of internet. However, you can always use the regular firewalling techniques like blocking all incoming traffic with a source address that is local to your network (and of course all RFC1918 traffic like 192.168.0.0/16), and use connection tracking (-m state --state ESTABLISHED, RELATED) to block most incoming traffic that is not a reply to outgoing connections, and then carefully allow what you like to come in. This has to be done separately for the external interface and the tunnel interface, as the things you want to allow on those two interfaces are completely different. Lots of firewall howto's only show you how to put lots of rules in the INPUT or FORWARD table, which quickly make things inefficient and difficult to maintain. It is usually better to setup a number of tables with iptables -N tablename, each with the rules for a specific interface or even for a protocol, and put rules in the INPUT and FORWARD tables that match on some input/output interface and branch to the table for that case. iptables -N eth0ipip .... iptables -N eth0input iptables -A eth0input -p 4 -j eth0ipip ... iptables -N tunl0input iptables -A INPUT -i eth0 -j eth0input iptables -A INPUT -i tunl0 -j tunl0input ... Rob

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Re: [44net] OpenWRT Security Notice
by Rob Janssen 02 Feb '16

02 Feb '16

> Subject: > [44net] OpenWRT Security Notice > From: > lleachii(a)aol.com > Date: > 02/02/2016 04:11 AM > > To: > 44net(a)hamradio.ucsd.edu > > > > the least computationally difficult method to protect our gateways from rogue packets is to not publicize/announce our Public WAN-facing IP address. Of course that does not work very well. All other gateway stations know your public IP and those who really want to know it can probably obtain it. The only way to protect your system is by using appropriate filters. And yes, these can be difficult to design, especially in the world of lousy internet service providers that do not bother filtering clients that spoof addresses.... Rob

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Re: [44net] NTP Server Test
by lleachii＠aol.com 01 Feb '16

01 Feb '16

All, - Time - NTP UDP/123 - This is odd, I'm able to reach the server and 44.60.44.1 from AMPR and the Public Internet (what exactly are you trying to 'reach' at 44.60.44.1 to determine its status, as I've only announced NTP as being available there) - using 'ntpdate -q 44.60.44.1' or 'ntpdate -q kb3vwg-001.ampr.org' works for me anywhere on the Internet kb3vwg@kb3vwg:~$ ntpdate -q 44.60.44.1 server 44.60.44.1, stratum 2, offset 0.001173, delay 0.02589 30 Jan 18:00:19 ntpdate[1058]: adjust time server 44.60.44.1 offset 0.001173 sec - I have now permitted access from the Public Internet (previously, it was only available to 44 hosts), let me know - Lynwood KB3VWG

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Re: [44net] Just received allocation... next steps?
by lleachii＠aol.com 01 Feb '16

01 Feb '16

Stephen and Ed, I have setup the tunneling routers on devices using OpenWRT and Ubuntu Linux. Since OpenWRT is actually designed to be a router OS, I highly suggest it. There are instructions for setting up a gateway using both OSes at http://wiki.ampr.org/ In order to route using Ubiquiti or VyOs, you must be able to compile and run ampr-ripd in order to provide RIP44 (which is not the name as RIPv2) on the tunnel interface. Since VyOs is a distribution of Linux, there may be instructions on the Internet on how to compile and/or execute ampr-ripd or rip44d. 73, Lynwood KB3VWG

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Just received allocation... next steps?
by Stephen - K1LNX 01 Feb '16

01 Feb '16

Hi guys, I just received an allocation for 44.34.96.0/24 to begin experimenting with. I plan on doing mesh networking as well as offering services as time permits. I have two questions regarding connectivity to the network: - I understand most folks are doing IPIP tunneling, has anyone ever done this on a Ubiquiti Edgerouter Lite or VyOS? Anyone in or near Tennessee that can accomodate a tunnel for me? - BGP... thinking entirely out loud here, but are there any VPS providers anyone is aware of that will accept announcements from 44 net that I could handle with say BIRD or another BGP daemon under linux? This would be my ideal setup and I could tunnel my own connectivity, but not sure this is possible.. looking for ideas here. 73, and glad to be a part of AMPR, I love networking :) Stephen K1LNX

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NTP - Reference
by lleachii＠aol.com 01 Feb '16

01 Feb '16

An inquiry was made into the Stratum of the NTP server: - Servers referenced are Stratum 1 or Stratum 2 Servers which reference a Stratum 0 Atomic Clock maintained by a University or Government Institution in Canada, the US or Mexico time-d.nist.gov nist1-pa.ustiming.org time.nist.gov time.nrc.ca time.chu.nrc.ca gnomon.cc.columbia.edu tick.gatech.edu cronos.cenam.mx

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44net February 2016