[nos-bbs] JNOS axudp to BPQ on the same host?

[Boudewijn (Bob) Tenty]

Linux just picks whatever address is convenient to reach the target. You can bind several addresses to the kernel (I do),
but make it so that they serve different target address groups, so that the kernel has no choice but to pick the right source
address to reach the target. In your case you should use only one 192.168.. address for the kernel, as you have found out :-)

Bob VE3TOK

On 2020-09-07 23:11, Darin Franklin wrote:
> I ended up installing BPQ on another host, 192.168.1.103, and I got that to work.  On 192.168.1.103, I saw that the UDP packets were arriving with a source address of 192.168.2.2, but I couldn't ping that from 192.168.1.103.  I added a route to 192.168.2.2 in my router, pointing it to gateway 192.168.1.102.  With that, I was able to connect both ways.
>
> I also got the Internet connection to work by adding port forwarding in the router: 10093 UDP goes to 192.168.2.2.
>
> I could not get JNOS to connect to BPQ on the same host using 192.168.1.102.  It only works if I send to 192.168.2.1.
>
> Ping from JNOS does work.
>
> jnos> ping 192.168.1.102
> jnos> Resolving 192.168.1.102... 192.168.1.102: rtt 1
>
> % sudo tcpdump  -i tun0 -n -vvv -p icmp
> tcpdump: listening on tun0, link-type RAW (Raw IP), capture size 262144 bytes                                                       
> 21:12:40.561676 IP (tos 0x0, ttl 254, id 60, offset 0, flags [none], proto ICMP (1), length 32)                                     
>     192.168.2.2 > 192.168.1.102: ICMP echo request, id 132, seq 0, length 12                                                        
> 21:12:40.561806 IP (tos 0x0, ttl 64, id 23618, offset 0, flags [none], proto ICMP (1), length 32)                                   
>     192.168.1.102 > 192.168.2.2: ICMP echo reply, id 132, seq 0, length 12                                                          
>
> I think that problem is in BPQ. It looks like it is receiving the message on 192.168.1.102, but it is sending the reply from 192.168.2.1.  There is not a way to make it bind to a single IP address.
>
> % sudo tcpdump  -i tun0 -n -vvv -u port 10092
> tcpdump: listening on tun0, link-type RAW (Raw IP), capture size 262144 bytes                                                       
> 21:47:12.795131 IP (tos 0x0, ttl 254, id 17, offset 0, flags [none], proto UDP (17), length 45)                                     
>     192.168.2.2.10092 > 192.168.1.102.10092: [udp sum ok] UDP, length 17                                                            
> 21:47:12.910736 IP (tos 0x0, ttl 64, id 5353, offset 0, flags [DF], proto UDP (17), length 45)                                      
> 192.168.2.1.10092 > 192.168.2.2.10092: [udp sum ok] UDP, length 17                                                              
>
> Anyway, that is a moot point now, since I have the remote hosts working.  I thought that running them on the same box would be easier to troubleshoot, but it just caused more trouble.
>
>
>> On Sep 7, 2020, at 7:15 AM, M Langelaar <maiko at pcsinternet.ca> wrote:
>>
>> Hi Darin,
>>
>>> I use 192.168.1.102 (the RPi host address), then I cannot connect to BPQ.
>>> attach axudp bpq 256 192.168.1.102 KE0NUC-3 10092 10092
>>> jnos> c bpq KE0NUC-3
>>> Trying KE0NUC-3 on port bpq...
>>> (wait forever...)
>>>
>>> How do I get this second case to work?
>> I don't know if that's the complete networking side of BPQ configuration
>> you gave, but it's almost like you don't have IP forwarding enabled on linux.
>>
>> Can you telnet (or probe ssh using telnet 22) from JNOS to your PI ?
>>
>> May I ask why you want to switch from 192.168.2 to your PI address instead ?
>>
>> Maiko, VE4KLM
>>
>
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