3 ms·

Also: - MAC addresses are unique. - LANs won't be bridged. - Spanning tree will converge quickly. - Quickly enough that it will beat BIOS getting to DHCP fo

Also: - MAC addresses are unique. - LANs won't be bridged. - Spanning tree will converge quickly. - Quickly enough that it will beat BIOS getting to DHCP for netbooting. - There will only be one circuit in the network so you can disable spanning tree. - The path MTU will be at least 1500 (or 9000, or x). - Path MTU discovery will work. - Packets with DF bit set won't be fragmented. - ICMP won't be dropped. - Network circuits will be the same path in both directions. - There will be one NIC / a default route. - The domain name 'localhost' will always resolve to localhost, or 127.0.0.1. - A DNS responder exists on the network. - It is a good idea to try to resolve IP addresses as names. - A device will use IPv4 by default (some systems opportunistically look for A and AAAA addresses and try both). - All networks have a path to the internet. - There will be no proxy required, or - The proxy won't require a login, or - The proxy credentials won't have a backslash. I'm diverging higher up the stack at this point so I'll stop.

nieve 10y ago
> MAC addresses are unique Or at least they're unique on a single machine... except for the various OSes and hardware platforms that have deliberately made all MAC addresses the same for a given machine.
- angry_octet 10y ago
  Ah, the old weak host model quirk of Linux IP stack and helpful RHEL6 (https://technet.microsoft.com/en-us/library/2007.09.cableguy.aspx https://technet.microsoft.com/en-us/library/2007.09.cableguy...). I'm not quite sure why it came about though. One more: - There will never be more than 1000/2000/... MAC addresses per subnet.
- tonyarkles 10y ago
  Way back in the land before time, I acquired a number of old 486s and ISA NICs. Being a good Slashdot nerd, I of course thought "lets make a Beowulf cluster of these!" So I've got the cluster set up, and it's mostly working. There's two nodes though that behave funny. Imagine my surprise when I try pinging one of them and get two responses per ping! Sure enough, two ISA NICs pulled randomly out of a box of garbage indeed had identical MACs. I learned a lot about IP and the MAC layer from that project!

nieve 10y ago

> MAC addresses are unique Or at least they're unique on a single machine... except for the various OSes and hardware platforms that have deliberately made all MAC addresses the same for a given machine.

angry_octet 10y ago
Ah, the old weak host model quirk of Linux IP stack and helpful RHEL6 (https://technet.microsoft.com/en-us/library/2007.09.cableguy.aspx https://technet.microsoft.com/en-us/library/2007.09.cableguy...). I'm not quite sure why it came about though. One more: - There will never be more than 1000/2000/... MAC addresses per subnet.
tonyarkles 10y ago
Way back in the land before time, I acquired a number of old 486s and ISA NICs. Being a good Slashdot nerd, I of course thought "lets make a Beowulf cluster of these!" So I've got the cluster set up, and it's mostly working. There's two nodes though that behave funny. Imagine my surprise when I try pinging one of them and get two responses per ping! Sure enough, two ISA NICs pulled randomly out of a box of garbage indeed had identical MACs. I learned a lot about IP and the MAC layer from that project!