arp who-has? tell?
ron
macroron at gmail.com
Thu Dec 20 16:42:11 UTC 2007
Jacques B. said:
> I can see the 98.203.0.1 entries being potentially normal. Depending
> how they set things up, you could have an entire street or
> neighbourhood on a subnet. ARP requests are broadcast ARPs which
> would be seen by all hosts on the subnet, so normal traffic. I am at
> a lost for explaining the ARP requests coming from other ranges of IPs
> that are no doubt not in your subnet. What is your subnet mask? That
> would help determine what broadcast traffic you should see.
>
> Jacques B.
>
> Further to my last message, what is your default gateway as well (I'm
> guessing 93.203.0.1 but I shouldn't assume)?
> Jacques B.
John Cornelius said:
> Actually, these messages are coming from the DHCP server for the physical segment (not subnet) that the modem is on. It's
> updating its tables of active addresses so that it can put inactive ones back into the mix for subsequent allocation to other
> sites. The 98.203.0.1 address is the address of the DHCP server.
> ARP requests are done at the network's physical layer because interfaces are not guaranteed to have an IP address so while > subnet masks don't effect them physical segmentation does.
> It's pretty normal for cable internet providers to do this to keep their tables up to date. They can also have more than one
> network on a physical segment which might explain the "strange" addresses.
> Finally, all interfaces will generate ARP requests because when you try to make a connection to an IP address on the same
> subnet you don't know what its physical address is so your computer issues an ARP request of the form "who has
> nn.nn.nn.nn". Whoever has that address responds with its physical address and then you can make your connection. All
> ethernet communications is ultimately done between physical addresses which may explain why we go to all of this trouble.
> --jc
Some info:
$ sudo /sbin/ifconfig
eth0 Link encap:Ethernet HWaddr 00:11:D8:CF:C4:8C
inet addr:98.203.6.135 Bcast:255.255.255.255 Mask:255.255.248.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:582667 errors:0 dropped:0 overruns:0 frame:0
TX packets:178013 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:368010009 (350.9 MiB) TX bytes:17358499 (16.5 MiB)
Interrupt:17 Base address:0x2000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:910 errors:0 dropped:0 overruns:0 frame:0
TX packets:910 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2490948 (2.3 MiB) TX bytes:2490948 (2.3 MiB)
--
As far as my default gateway I'm guessing 93.203.0.1
$ cat etc hosts:
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost f8
::1 localhost.localdomain localhost f8
--
Sorry I'm new at this.
Thanks for the reply. I figured it somehow is programmed into the
cable modem and is somehow initiated by Comcast. I initially ignored
it, but as a start in my learning about routers and networking I
started here. I basically see how it works now. My next project is to
get a static ip address from DynDNS www.dyndns.com/ and then study up
on routers. Any sugestions on hardware and software would be
appreciated. I'd like to eventually experiment with a wireless sff
motherboard diy router project.
Thanks again.
-macroron-
More information about the users
mailing list