On Thu, May 6, 2010 at 13:35, Kevin Ross <ke...@familyross.net> wrote:
> On 5/6/2010 12:05 AM, Alex Samad wrote: > >> >> well think about it, if we are talking about network 192.168.11.0/24 >> (for my example I will use 24 instead of 27) >> >> the server would have an address 192.168.11.55/24 (for example) and the >> router would have 192.168.11.1/24 >> >> if I change the netmask of the server it can no longer talk to the >> router because it is in a different ip network ie 192.168.11.55/22 can't >> talk to 192.168.11.1/24 (you can fake it on linux with iproute - see my >> other answer to this thread). >> >> > > Sorry if I'm being dense, I said I'm not a networking expert. But I have > thought about this, and I am not seeing how it wouldn't work. > > 192.168.11.1 is: > 11000000 10101000 00001011 00000001 > > 192.168.11.55 is: > 11000000 10101000 00001011 00110111 > > So, the computer at 192.168.11.55 will think it's subnet is the first 22 > bits of the address, which is 11000000 10101000 000010, which matches the > first 22 bits of the router address. So far so good. Client side will > think the machine at 192.168.11.1 is on the same IP subnet, so it will do an > ARP request for 192.168.11.1 (ARP doesn't care about subnet masks, it just > does an Ethernet broadcast), which will succeed, and the server will be able > to send to the router. The reverse direction is also true. > > What am I missing? > > > > -- > To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a > subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org > Archive: http://lists.debian.org/4be27852.6010...@familyross.net @Kevin Ross You are correct. Nice explation with details. Just to see what happens when two different networks/broadcast domain on the same switch, I updated my configuration below. router: 192.168.1.1/255.255.255.0 pc1: cat /etc/network/interfaces auto eth0 iface eth0 inet static address 192.168.1.50 netmask 255.255.255.0 gateway 192.168.1.1 auto eth0:0 iface eth0:0 inet static address 192.168.10.50 netmask 255.255.255.0 broadcast 192.168.10.255 pc2: cat /etc/network/interfaces auto eth0 iface eth0 inet static address 192.168.1.100 netmask 255.255.255.0 gateway 192.168.1.1 auto eth0:0 iface eth0:0 inet static address 192.168.10.100 netmask 255.255.255.0 broadcast 192.168.10.255 pc1 and pc2 could reach each other using both 192.168.1.0/24 and 192.168.10.0/24 addresses. Also they could access the router and internet using 192.168.1.0/24 address. Then I changed pc2 to be. pc2: cat /etc/network/interfaces auto eth0 iface eth0 inet static address 192.168.10.100 netmask 255.255.255.0 With this pc2 could only access pc1 using 192.168.10.0/24 address. It could not access the router or internet.
