| Rev | Author | # | Line |
|---|---|---|---|
| 1 | PerryLorier | 1 | See also NetworkingBestPractices |
| 2 | PerryLorier | 2 | ---- |
| 3 | !! Use of RFC:1918 addresses for routers | ||
| 4 | This has issues such as: | ||
| 3 | JohnMcPherson | 5 | <verbatim> |
| 6 | [Host A] <-> [Router B] <-> [Router C] <-> [Router D] <-> [Router E] <-> [Host F ] | ||
| 7 | </verbatim> | ||
| 2 | PerryLorier | 8 | |
| 9 | Now, Router B has a route to some RFC:1918 space (perhaps Host A is even on RFC:1918 behind [NAT]), Router D is numbered using RFC:1918 space (differently routable than Router B). Now, if the link from Router D and router E has a smaller [MTU] than the rest of the network, and Router B has reverse path filtering on, then A can no longer talk to F. If A traceroutes to F then it misses seeing D as well for the same reason. | ||
| 10 | |||
| 11 | RFC:1918 is evil and should be avoided at all costs, if you must use it, use it only on the edges on networks you control. | ||
| 3 | JohnMcPherson | 12 | |
| 13 | !! IP Aliases | ||
| 14 | Network interfaces can be assigned more than one [IP] address. | ||
| 15 | |||
| 16 | Eg, to create aliases for the range 192.168.0.1 - 192.168.0.20: | ||
| 17 | |||
| 18 | ![FreeBSD]: | ||
| 19 | <verbatim> | ||
| 20 | for i in `jot 20 1` ; | ||
| 21 | do | ||
| 22 | ifconfig fxp0 inet 192.168.0.$i alias ; | ||
| 23 | done | ||
| 24 | </verbatim> | ||
| 25 | |||
| 26 | !Linux distros: | ||
| 27 | (old way)%%% | ||
| 28 | <verbatim> | ||
| 29 | for i in `seq 1 20` ; | ||
| 30 | do | ||
| 31 | ifconfig eth0:$i 192.168.0.$i ; | ||
| 32 | done | ||
| 33 | </verbatim> | ||
| 34 | |||
| 35 | (new way)%%% | ||
| 36 | <verbatim> | ||
| 37 | for i in `seq 1 20` ; | ||
| 38 | do | ||
| 39 | ip addr add 192.168.0.$i dev eth0 ; | ||
| 40 | done | ||
| 41 | </verbatim> | ||
| 42 | This also lets you assign a range, eg: | ||
| 43 | <verbatim> | ||
| 44 | ip addr add 192.168.0.0/24 dev eth0 | ||
| 45 | </verbatim> | ||
| 46 | However, old tools like route(8) and ifconfig(8) won't show you anything added using this method. | ||
| 47 | |||
| 48 | ---- | ||
| 49 | !!!Other | ||
| 50 | This page discusses the difference in tuning networking on various OS's: http://foureleven.org:81/rosetta-stone-performance-tuning.html | ||
| 1 | PerryLorier | 51 | |
| 52 | ---- | ||
| 53 | CategoryNetworking |
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