I have a Debian box, and for some reason today it can't connect to my network. The router uses the address 192.168.2.1 and the Debian box uses 192.168.2.51. This has always worked, but for some reason it can't ping to any host and can't be pinged by other hosts. Pinging to 127.0.0.1 does work, so the IP stack is working fine. Also tried a different address and DHCP, to no avail. I do notice that while booting up, it shows the message "Starting MTA", and keeps waiting at that message for about 20 seconds. What could be the cause? Both the network adapter and the cable appear to be working fine, because I've tested them in other systems. What could be the cause?