I’ve just picked up a nice new entry on the “Falsehoods [people] believe about [topic]” meme … this one is “Falsehoods programmers believe about networks” and comes from Errata Security, a very good resource.
Here’s the top 5 :-
- Data on the network cannot be altered.
- Encrypted data on the network cannot be altered.
- Data cannot be accidentally corrupted, because TCP has checksums and Ethernet has CRCs
- If it’s inside my perimeter firewall, that means I have total control over it
- If it doesn’t return an error, then send() sent all the data that was asked of it.
A small list at the end is “Falsehoods network administrators believe about networks” …
- There is no IPv6 on my network
- NAT automatically blocks all inbound attacks
- We know all the devices attached to our network at any given time
- There are always 24 hours in a day.
- Months have either 30 or 31 days.
- Years have 365 days.
- February is always 28 days long.
- Any 24-hour period will always begin and end in the same day (or week, or month).
- People have exactly one canonical full name.
- People have exactly one full name which they go by.
- People’s names fit within a certain defined amount of space.
- People’s names do not change.
- People’s names change, but only at a certain enumerated set of events.
- People’s names are written in ASCII.
- People’s names are written in any single character set.
- People’s names are all mapped in Unicode code points.
- People’s names are case sensitive.
- People’s names are case insensitive.