<div dir="ltr">Hi Glenn,<div>My linux interface is a DHCP client which is connected to a night hawk (cradlepoint) which acts as the DHCP server. So my Linux interface is getting a DHCP IP address as gievn below</div><div><br></div><div><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">eth1.15 Link encap:Ethernet HWaddr
00:08:A2:00:00:02</p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"> inet
addr:<b>192.168.1.76 </b> Bcast:192.168.1.255 Mask:255.255.255.0</p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"> UP
BROADCAST RUNNING MULTICAST MTU:1500 Metric:1</p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"> RX
packets:457 errors:0 dropped:0 overruns:0 frame:0</p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"> TX
packets:1782 errors:0 dropped:0 overruns:0 carrier:0</p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">
collisions:0 txqueuelen:0</p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"> RX
bytes:44717 (43.6 KiB) TX bytes:1704498 (1.6 MiB)</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><br></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><br></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">The kernel routing table is below. I did not see any default GW in the routing table.</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><br></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">Kernel IP routing table</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">Destination
Gateway
Genmask Flags MSS
Window irtt Iface</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">10.64.64.67
0.0.0.0 255.255.255.255
UH 0
0 0 ppp3</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">10.64.64.66
0.0.0.0 255.255.255.255
UH 0
0 0 ppp2</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">10.64.64.65
0.0.0.0 255.255.255.255
UH 0
0 0 ppp1</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">255.255.255.255
0.0.0.0 255.255.255.255
UH 0
0 0 eth1.13</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><b>192.168.1.0
0.0.0.0
255.255.255.0 U 0
0 0 eth1.15</b></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">128.0.0.0
0.0.0.0
255.255.255.0 U 0
0 0 eth1.16</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">128.1.0.0
0.0.0.0
255.255.0.0
U 0
0 0 eth0</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">
</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">10.20.0.0
0.0.0.0
255.255.0.0
U 0
0 0 eth1.13</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><br></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">Regards</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">Simon</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><br></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><br></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><br></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><br></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"> </p></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Mar 18, 2021 at 8:48 PM <<a href="mailto:glenn.satchell@uniq.com.au">glenn.satchell@uniq.com.au</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi Simon,<br>
<br>
On your dhcp server do you specify a gateway? For isc dhcpd it will be <br>
"option routers" in the subnet definition settings. Verify that the <br>
gateway you specify is in the same subnet as the IP address being <br>
assigned to the interface.<br>
<br>
Can you post the output from "ip route" and "ip address" so we can see <br>
what is there?<br>
<br>
If you are configuring the IP address manually then it depends on your <br>
particular version of linux on how that is done. Usually you will <br>
specify an IP address, netmask and gateway- but the files used vary from <br>
distribution to distribution. eg Ubuntu uses /etc/netplan/*yaml or <br>
/etc/network/interfaces depending on the version. CentOS uses <br>
/etc/sysconfig/network-scripts/ifcfg-eth0. Or it may use Network Manager <br>
and the associated GUI to manage the configuration.<br>
<br>
regards,<br>
Glenn<br>
<br>
On 2021-03-19 14:34, SIMON BABY wrote:<br>
> Hi Glenn,<br>
> It did not show the default route of <a href="http://0.0.0.0/0" rel="noreferrer" target="_blank">0.0.0.0/0</a> [1] with route -n. One<br>
> thing I noticed is, I can ping to another Address only with -I<br>
> interface_name. For example I can send and receive packets with ping<br>
> -I eth0 8.8.8.8.<br>
> If I use ping 8.8.8.8 it is not working. Am I missing anything here?<br>
> <br>
> Regards<br>
> Simon<br>
> <br>
> On Thu, Mar 18, 2021 at 8:15 PM <<a href="mailto:glenn.satchell@uniq.com.au" target="_blank">glenn.satchell@uniq.com.au</a>> wrote:<br>
> <br>
>> Hi Simon,<br>
>> <br>
>> The default route will show up with a destination of <a href="http://0.0.0.0/0" rel="noreferrer" target="_blank">0.0.0.0/0</a> [1]<br>
>> if you<br>
>> use route -n.<br>
>> <br>
>> If you use "ip route" it will show up with a destination of<br>
>> "default" in<br>
>> the first column.<br>
>> <br>
>> regards,<br>
>> Glenn<br>
>> <br>
>> On 2021-03-19 13:54, SIMON BABY wrote:<br>
>>> Hi Peter,<br>
>>> Thank you so much for helping.<br>
>>> <br>
>>> Yes, I am using ISC dhcpd. My query is with ISC DHCPd I can ping<br>
>> to<br>
>>> any network, but I did not see the ISC gateway in the kernel route<br>
>>> table. Will it be stored somewhere else so that when packet goes<br>
>> out,<br>
>>> the hardware (NIC) gets this information?<br>
>>> <br>
>>> Regards<br>
>>> Simon<br>
>>> <br>
>>> On Thu, Mar 18, 2021 at 5:07 PM Peter Yardley<br>
>>> <<a href="mailto:peter.martin.yardley@gmail.com" target="_blank">peter.martin.yardley@gmail.com</a>> wrote:<br>
>>> <br>
>>>> Hi,<br>
>>>> <br>
>>>> This is prolly a problem with your configuration. Are you using<br>
>> ISC<br>
>>>> DHCPd? If so could provide a relevant snippet of your<br>
>> configuration,<br>
>>>> anonymised if necessary.<br>
>>>> <br>
>>>> I used to configure subnets like this …<br>
>>>> <br>
>>>> subnet 10.20.50.0 netmask 255.255.254.0 {<br>
>>>> option subnet-mask 255.255.254.0;<br>
>>>> option broadcast-address 10.20.51.255;<br>
>>>> option routers 10.20.50.1;<br>
>>>> <br>
>>>> pool {<br>
>>>> # A device for Blah<br>
>>>> host HMTXYZ { hardware ethernet 00:40:9d:54:4c:c7;<br>
>>>> fixed-address 10.20.50.32; }<br>
>>>> …<br>
>>>> <br>
>>>> range 10.20.51.0 138.25.51.254;<br>
>>>> }<br>
>>>> <br>
>>>> Of course there are many other correct possiblities<br>
>>>> <br>
>>>>> On 19 Mar 2021, at 10:03 am, SIMON BABY <<a href="mailto:simonkbaby@gmail.com" target="_blank">simonkbaby@gmail.com</a>><br>
>>>> wrote:<br>
>>>>> <br>
>>>>> Hi,<br>
>>>>> I have a query about the DHCP provided IP address vs Static IP<br>
>>>> address configured manually. When i get the IP address from<br>
>> DHCP, I<br>
>>>> can ping to 8.8.8.8 (google public server) where as<br>
>>>>> with a statically configured IP address, I could not. When I<br>
>>>> looked into the route table (route -n ), I did not see any<br>
>> default<br>
>>>> gateway with DHCP or Statically configured IP. (I am testing<br>
>> with<br>
>>>> Linux).<br>
>>>>> <br>
>>>>> 1. Can I know when the packet goes out , how did the hardware<br>
>>>> (NIC) find the default gateway in the case of the DHCP provided<br>
>> IP<br>
>>>> address since I did not see any default gw IP in the routing<br>
>> table?<br>
>>>>> 2. With statically configured IP, if I explicitly configure a<br>
>>>> default GW, I can see packets are going out and receiving. I can<br>
>> see<br>
>>>> the default GW in the routing table. Do I need a default GW to<br>
>> send<br>
>>>> packets from a statically configured IP address ?<br>
>>>>> <br>
>>>>> Thank you for your time<br>
>>>>> <br>
>>>>> Regards<br>
>>>>> Simon<br>
>>>>> <br>
>>>>> _______________________________________________<br>
>>>>> ISC funds the development of this software with paid support<br>
>>>> subscriptions. Contact us at <a href="https://www.isc.org/contact/" rel="noreferrer" target="_blank">https://www.isc.org/contact/</a> for<br>
>> more<br>
>>>> information.<br>
>>>>> <br>
>>>>> dhcp-users mailing list<br>
>>>>> <a href="mailto:dhcp-users@lists.isc.org" target="_blank">dhcp-users@lists.isc.org</a><br>
>>>>> <a href="https://lists.isc.org/mailman/listinfo/dhcp-users" rel="noreferrer" target="_blank">https://lists.isc.org/mailman/listinfo/dhcp-users</a><br>
>>>> <br>
>>>> Peter Yardley<br>
>>>> <a href="mailto:peter.martin.yardley@gmail.com" target="_blank">peter.martin.yardley@gmail.com</a><br>
>>>> <br>
>>>> _______________________________________________<br>
>>>> ISC funds the development of this software with paid support<br>
>>>> subscriptions. Contact us at <a href="https://www.isc.org/contact/" rel="noreferrer" target="_blank">https://www.isc.org/contact/</a> for<br>
>> more<br>
>>>> information.<br>
>>>> <br>
>>>> dhcp-users mailing list<br>
>>>> <a href="mailto:dhcp-users@lists.isc.org" target="_blank">dhcp-users@lists.isc.org</a><br>
>>>> <a href="https://lists.isc.org/mailman/listinfo/dhcp-users" rel="noreferrer" target="_blank">https://lists.isc.org/mailman/listinfo/dhcp-users</a><br>
>>> _______________________________________________<br>
>>> ISC funds the development of this software with paid support<br>
>>> subscriptions. Contact us at <a href="https://www.isc.org/contact/" rel="noreferrer" target="_blank">https://www.isc.org/contact/</a> for more<br>
>>> information.<br>
>>> <br>
>>> dhcp-users mailing list<br>
>>> <a href="mailto:dhcp-users@lists.isc.org" target="_blank">dhcp-users@lists.isc.org</a><br>
>>> <a href="https://lists.isc.org/mailman/listinfo/dhcp-users" rel="noreferrer" target="_blank">https://lists.isc.org/mailman/listinfo/dhcp-users</a><br>
>> _______________________________________________<br>
>> ISC funds the development of this software with paid support<br>
>> subscriptions. Contact us at <a href="https://www.isc.org/contact/" rel="noreferrer" target="_blank">https://www.isc.org/contact/</a> for more<br>
>> information.<br>
>> <br>
>> dhcp-users mailing list<br>
>> <a href="mailto:dhcp-users@lists.isc.org" target="_blank">dhcp-users@lists.isc.org</a><br>
>> <a href="https://lists.isc.org/mailman/listinfo/dhcp-users" rel="noreferrer" target="_blank">https://lists.isc.org/mailman/listinfo/dhcp-users</a><br>
> <br>
> <br>
> Links:<br>
> ------<br>
> [1] <a href="http://0.0.0.0/0" rel="noreferrer" target="_blank">http://0.0.0.0/0</a><br>
> _______________________________________________<br>
> ISC funds the development of this software with paid support<br>
> subscriptions. Contact us at <a href="https://www.isc.org/contact/" rel="noreferrer" target="_blank">https://www.isc.org/contact/</a> for more<br>
> information.<br>
> <br>
> dhcp-users mailing list<br>
> <a href="mailto:dhcp-users@lists.isc.org" target="_blank">dhcp-users@lists.isc.org</a><br>
> <a href="https://lists.isc.org/mailman/listinfo/dhcp-users" rel="noreferrer" target="_blank">https://lists.isc.org/mailman/listinfo/dhcp-users</a><br>
_______________________________________________<br>
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</blockquote></div>