I've been upgrading my installation of the Debian distro using apt-get. I must say that this appears to be a rather easy way to keep current.

I have a question, though, that I think is not distro specific. After doing an apt-get dist-upgrade successfully, I noticed I couldn't get beyond my ISP's subnet router, out to the internet. I might add here that I have cable. So any user, including the router, on my subnet, I could 'ping'. However, if I tried to ping my ISP's DNS server, I'd get no response.

After looking around, doing netstat -rn and ifconfig -a, I noticed that I had a new interface called tap0. If I ifconfig tap0 down, I had normal Internet access again.

Can anyone tell me what package, firewall, proxy server, ipchains or whatever created this interface?

TIA -mk

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If it ain't broke, fix it till it is.