Debian network disappearing

Question

I'm running Debian v8 (systemd purged and systemV installed ... works fine). It is a clean installation (Debian v7 used to be on this machine) The harddrives failed after numerous power failures on 1 day. I restored all configuration files from my backups i.e: network, squid, proftp, mysql, apache, iptables etc.

This Debian 8 machine interacts (or is supposed to rather) with other servers (samba, serviio, ftp, mysql) on the internal network. The problem I am experiencing is that the internet (and connections to the other machines on the local network) disappears after a few seconds and I am unable to ping the router although I can ping the wireless card (wlan0) and ethetnet card (eth0) on this Debian 8 machine.

I have hostapd setup between wlan0 and eth0 via br0 to give people wireless access to the internet. I am stumped as to what the problem might be as I have checked and re-checked everything from my backups.

This Debian v8 machine network config is this:

wlan0 -----> br0 -------> eth0 -----> router ----> internet  
(10.0.0.5)-> (10.0.0.4)-> (10.0.0.3)->(10.0.0.2)-> internet  
____^___ (All local machines connect through wlan0)

Bind9 works fine. Interfaces comes up fine.

Like I said, I can ping 10.0.0.5/4/3 with no problem but cannot ping the router or any other machine on the network. The network is 10.0.0.0/24 with netmask 255.255.255.0.

Here is my routing table:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         10.0.0.2        0.0.0.0         UG    0      0        0 eth0
link-local      *               255.255.255.0   U     0      0        0 eth0
link-local      *               255.255.255.0   U     0      0        0 br0
link-local      *               255.255.255.0   U     0      0        0 wlan0

Here is iptables:

# Generated by iptables-save v1.4.21 on Thu Jun 11 10:35:35 2015
*mangle
:PREROUTING ACCEPT [403:63515]
:INPUT ACCEPT [385:56330]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [432:59142]
:POSTROUTING ACCEPT [432:59142]
COMMIT
# Completed on Thu Jun 11 10:35:35 2015
# Generated by iptables-save v1.4.21 on Thu Jun 11 10:35:35 2015
*filter
:INPUT ACCEPT [385:56330]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [432:59142]
#-A INPUT -i eth0 -p tcp -m tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
-A FORWARD -s 10.0.0.0/24 -i eth0 -o wlan0 -m conntrack --ctstate NEW -j ACCEPT
-A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
COMMIT
# Completed on Thu Jun 11 10:35:35 2015
# Generated by iptables-save v1.4.21 on Thu Jun 11 10:35:35 2015
*nat
:PREROUTING ACCEPT [19:7421]
:INPUT ACCEPT [1:236]
:OUTPUT ACCEPT [55:3490]
:POSTROUTING ACCEPT [0:0]  
# Below is for routing local network http requests (port 80) to squid 3128
#-A PREROUTING -s 10.0.0.0/24 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128
#-A PREROUTING -i wlan0 -p tcp -m tcp --dport 80 -j DNAT --to-destination 10.0.0.5:3128
-A POSTROUTING -j MASQUERADE
COMMIT
# Completed on Thu Jun 11 10:35:35 2015

Here is my interfaces file:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

iface eth0 inet static
    address 10.0.0.3
    netmask 255.255.255.0
    network 10.0.0.0
    hwaddress e7:df:12:00:1g:63
    broadcast 10.0.0.255
    dns-nameservers 10.0.0.5 10.0.0.2
    dns-search 10.0.0.5 10.0.0.2
    gateway 10.0.0.2
auto eth0

iface wlan0 inet static
    mode infrastructure
    wireless-mode master
    wireless-essid "fever"
    wireless-channel 1
    address 10.0.0.5
    netmask 255.255.255.0
    network 10.0.0.0
    gateway 10.0.0.2
    hwaddress 1d:dd:b2:2a:ae:1d
    broadcast 10.0.0.255
    dns-nameservers 10.0.0.5 10.0.0.2
    dns-search 10.0.0.5 10.0.0.2
auto wlan0

## Setup the bridge
iface br0 inet static
  bridge-ports wlan0 eth0
  address 10.0.0.4
  netmask 255.255.255.0
  network 10.0.0.0
  gateway 10.0.0.2
  dns-nameservers 10.0.0.5 10.0.0.2
  dns-search 10.0.0.5 10.0.0.2
auto br0

Here is my hostapd.conf:

interface=wlan0
bridge=br0
driver=nl80211
country_code=ZA
ssid=fever
hw_mode=g
channel=6
wpa=2
wpa_passphrase=123abc123
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP
auth_algs=1
macaddr_acl=0
ignore_broadcast_ssid=0

All traces of Network-Manager (therefore Gnome) has been purged together with wicd. I have isc-dhcp-server which serves IP addresses on wlan0.

I have noticed that /etc/resolv.conf (which points to /etc/resolvconf/run/resolv.conf) sometimes disappears and when it is there it is empty.

If I disable hostapd and remove br0 I can access the internet. So there is some interference from somewhere if I enable hostapd and br0 which only works for a few seconds if they are enabled.

I have no dhcp-client ... I have wpa_supplicant and the normal wireless-tools installed.

Answer 1

I am assuming that your IP config is identical to your previous install (debian 7) and therefore it should work now just as it did before. However, it is confusing to me that it did work as you have 3 routes to the local lan - eth0, wlan0, and br0.

I would only bind IP to br0. That should accomplish everything that you need and would reduce complexity. There is no need for 3 addresses all on the same subnet/bridged network.

I have a similar setup and my interfaces file looks more like this:

...
iface eth0 inet manual
    hwaddress e7:df:12:00:1g:63
auto eth0

iface wlan0 inet manual
    mode infrastructure
    wireless-mode master
    wireless-essid "fever"
    wireless-channel 1
    hwaddress 1d:dd:b2:2a:ae:1d
auto wlan0

## Setup the bridge
iface br0 inet static
  bridge-ports wlan0 eth0
  address 10.0.0.4
  netmask 255.255.255.0
  network 10.0.0.0
  gateway 10.0.0.2
  dns-nameservers 10.0.0.5 10.0.0.2
  dns-search 10.0.0.5 10.0.0.2
auto br0
...