Robert Thomas is moving offices. From the executive chambers of Juniper Networks to the cramped digs at Sequoia Capital-funded start-up Infoblox. In case you don’t know, Thomas was the chief executive officer of security appliance maker NetScreen Technologies, which Juniper bought for about $4 billion seven months ago. Kittu Kollari, the maverick behind Neoteris, which made quite a name for itself selling VPN appliances, will become VP and General Manager of Juniper Networks Security Products Group. NetScreen eventually bought Neoteris for $265 million. Juniper says Thomas’ exit was all part of the plan: Thomas was going to leave once the integration was complete. Apparently it is.

Thomas’ exit should get some tongues wagging in silicon Valley, what with recent exodus of executives from Juniper. Is Sequoia connection being used by Cisco to weaken the Juniper ranks? (Not that crazy a thought given the bitter fighting between the two router makers!) Why quit so quickly after the deal was closed? Hmm! When I posed this question to Thomas he dismissed it outright and claimed that he is not a big company guy and wants to work in a start-up environment. Also he did not want to be reporting to Scott Kriens. “My skill set is not to run a large group within a larger company,” says Thomas. Translation: there can only be one chief executive at one company.

Infoblox is a five-year-old company that makes appliances that makes tasks such as DNS, DHCP and Radius management a breeze. “We are in the network identity management space. Everyone who has a network needs a DNS server, and people right now do that using some open source software. That is a bit messy and Infoblox has made an appliance and easy to use GUI. I think the potential size of the market is huge and this is a possible IPO play,” says Thomas. “I understand the appliance market. I think philosophically we are doing the same thing as NetScreen, just different markets.” The company has 250 customers, mostly large Fortune 100 type companies. Rivals include Nominum.