How Many IPv6 IPs Does It Take To Hose Linux and VMware?

I’ve been doing a lot of IPv6 testing lately. My network engineers allocated a /64 to me, which gives me 18,446,744,073,709,551,616 available IPs. My new goal is to use each and every one of those IPs.

A few minutes getting my network guys to trunk the right VLANs into my test VMware setup, one “for” loop, “sprintf(“%x”, $i)”, and one system call (“ifconfig eth0 inet6 add”) and I know a few more things:

1) Somewhere around IP number 4,010 I ran into a limit in Red Hat Enterprise Linux AS 4’s networking subsystems, or in VMware ESX Server. No more data in or out on any protocol. Smells like a buffer size needs to grow. I expected this.

2) The VMware tools fed my VMware VirtualCenter implementation some crap, it stored the crap in the database, and then the VirtualCenter server process died. And wouldn’t restart, presumably because of the crap in the database. I had to nuke the database for it to work right again (hooray for test environments!). Smells like a buffer overflow or something. I did not expect this.

I don’t have more time to pursue this right now, as I have too much stuff to wrap up before I leave for San Francisco (w00t). I just thought my ten minute test had interesting results. 🙂 When I get back I’ll drag out a real machine to try, and compare the findings.