He then asked me a lot of questions about what type of work environment I was looking for. I told him about wanting to continue to be involved with the IETF community (if possible), being in the loop of (technological) progress, and having authority commensurate with responsibility. He seemed to pick up on the latter point, because he said he tries to run his group that way. However, he did warn me that there are times when people are expected to work as much as 80 hours per week, even handling customer issues directly. I said that wouldn't be a problem, since I've had to do that for most of my career anyway.
He then told me that he'd like me to come in for an in-person interview. He asked how much programming I had been doing during this period of unemployment, especially C programming. I said that I have written code in several languages, depending upon the project in question. He cautioned me that the interview would be very difficult, involving questions about data structures and algorithms in C, because the engineers on his team make the questions very difficult. He asked me how I felt about that, and I said that I would just do the best I can, and that everyone experiences the same feelings on these types of interviews.
So, we'll see. (Nothing has been scheduled yet because of the Memorial Day holiday weekend.) But one thing that is now very very clear to me is that there is no substitute for the type of interview practice I have been doing. The competition is too stiff, and the interviews themselves too challenging, not to spend time developing code, studying algorithms and data structures, getting involved with open-source projects and/or standards bodies, etc.