My old Asus router died a few weeks ago, so I thought I'd set up my Debian box to deal with routing my home network. I have a few complications, but I adapted my configuration from a previously working configuration, and I don't see why I am having intermittent problems. But I am having them! Every so often, my SSH connections to the router (and to the Xen virtual machines hosted by the router) just drop. I am unable to use the router's dns server. I can't ping the router. Etc. All of these things work most of the time, but break down intermittently, for a few minutes at a time. (I can provide more details, but I'm not sure what will be helpful)
# The loopback network interface auto lo iface lo inet loopback # Gigabit ethernet, internal network auto eth0 allow-hotplug eth0 iface eth0 inet manual # USB ethernet, internet auto eth1 allow-hotplug eth1 iface eth1 inet dhcp # Xen Bridge auto xlan0 iface xlan0 inet static bridge_ports eth0 address 10.47.94.1 netmask 255.255.255.0
As I understand it, this is sufficient to create the network interfaces, and even do some switching between Xen hosts and my eth0 interface. I installed and configured Shorewall to manage routing between the bridge and my internet-facing interface:
fw firewall net ipv4 lan ipv4
net eth1 detect dhcp,tcpflags,nosmurfs,routefilter,logmartians lan xlan0 detect dhcp,tcpflags,nosmurfs,routefilter,logmartians,routeback,bridge
net all DROP info fw net ACCEPT info all all REJECT info
DNS(ACCEPT) fw net DNS(ACCEPT) lan fw Ping(ACCEPT) lan fw ... and so on, these all work, when the router is accepting traffic at all.
Also, the router is currently "working", and I checked on a problematic client:
arp infrastructure infrastructure.mydomain (10.47.94.1) at 0:23:54:bb:7d:ce on en0 ifscope [ethernet]
I tried it when the router was down, and I (eventually) got the same response. It took about 30 seconds to return, though.