On 2020-08-02 19:03, Ed Greshko wrote:
On 2020-08-03 09:36, ToddAndMargo via users wrote:
> On 2020-08-02 18:26, Samuel Sieb wrote:
>> On 8/2/20 6:22 PM, ToddAndMargo via users wrote:
>>> I am not after what the gateway address is, but rather
>>>
>>> 1) if gateway is up or not
>>
>> That can only be determined by pinging it or something past it.
>
> That is one way of doing it, but it gives a lot
> more information than I want. It tell me the
> Internet is working. I am not testing that.
>
> I only want to know if the device is connected to the
> gateway and the gateway is up.
So, ping the gateway?
You are presuming I know anything about several
networks at this point
>
>>
>>> 2) if my device connected to the gateway that is up
>>
>> Since you should know which interface goes to the gateway, why isn't it
enough to check if the interface is connected?
>
> I am setting up my iptables so it is universal. This
> is only one of about 15 parameters I read from the
> system.
>
Define "connected to". If by mean "accessible" then a ping or may
do. That is assuming the gateway
is configured to respond to pings. "Connected" usually means a connection is
established. As in an
ssh session.
Presuming I know which device (eno2 in this instance),
is part of which network (192.168.250.0/24 in this
instance), this will tell me that I am connected to
the router of that network. And what that router is.
$ netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt
Iface
0.0.0.0 192.168.250.1 0.0.0.0 UG 0 0 0
eno2
192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0
virbr0
192.168.250.0 0.0.0.0 255.255.255.0 U 0 0 0
eno2
192.168.255.0 0.0.0.0 255.255.255.0 U 0 0