[EMAIL PROTECTED] wrote: > I am implementing and using a test bed simulating a huge amount of IP > clients, each preferable having a unique IP address. There is no, no > way to have an individual physical interface for each simulated > client so I use IP aliases. Currently it runs on Linux and there is a > limit of 256 IP addresses per interface, among other things due to a > hard array limit in Linux net-tools ifconfig. There also seems to be > other limitations like linear searches in net-tools as well as in > kernel networking code. Just changing the array limit changed the > problem to being one of stability and performance. > > So I became quite optimistic reading about Virtual Hosts and IP > aliases in the FreeBSD handbook chapter 11.9: > > http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/configtuning-vi > rtual-hosts.html > > "A given network interface has one "real" address, and may have any > number of "alias" addresses". > > So is this really true and where is the catch? Will a FreeBSD 6.0 > accept for example 8190 IP address aliases each on say five physical > Ethernet interfaces? Will IP addresses be manageable to add, list and > delete? And how much will networking performance degrade compared to > using just a few aliases?
After a short test I don't think 8190 aliases will be a problem. [EMAIL PROTECTED] ~ #ifconfig re0| grep inet | wc -l 18008 [EMAIL PROTECTED] ~ #ifconfig re0 -alias 192.168.10.100 [EMAIL PROTECTED] ~ #ifconfig re0| grep inet | wc -l 18007 [EMAIL PROTECTED] ~ #ifconfig re0 alias 192.168.10.100 [EMAIL PROTECTED] ~ #ifconfig re0| grep inet | wc -l 18008 I don't know if there is a performance degradation on better hardware, but for my re0 the ftp performance seems to be the same as with only one IP. The only "catch" I can see is that it takes a while to create a few thousand aliases ;-) On my AMD Athlon(tm) XP 1900+ (1578.59-MHz 686-class CPU) I get about five aliases per second. Fabian -- http://www.fabiankeil.de/
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