On Tue, 13 Dec 2016 21:13:43 +0530 Balaji J <ping2balaji@xxxxxxxxx> wrote: > Hi all, > > I am trying to setup a bridge with 2 interfaces attached to it in Router-1. > Interface-1: eth1 ==> EoGRE Tunnel interface(gretap) connecting to another > Router-2 where DHCP server is running. > Interface-2: eth2 ==> Trying to use DHCP to assign IP for this eth2 > interface from DHCP-Server running on Router-2. > > Basically the setup i am expecting is like: > (eth2)[Router-1](eth1:100.1.1.1) <----------EoGRE > Tunnel----->(eth0:100.1.1.254)[Router-2](DHCP-Server) > > Following are the setup i did to check the 1st stage to see if the > dhcp-discover broadcast is going out of Router-1 over EoGRE tunnel or not. > But i am not able to achieve the same. > > Can anyone please let me know what is missing here? Thanks in advance. > > Router-1: > 1) ip link add eogre type gretap local 100.1.1.1 remote 100.1.1.254 ==> > created gretap with endpoints. > 2) ip link set eogre up ==> brought the eogre interface up. > [root@centos]# ifconfig > eogre Link encap:Ethernet HWaddr 9E:25:FC:54:7F:F2 > inet6 addr: fe80::9c25:fcff:fe54:7ff2/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1462 Metric:1 > RX packets:0 errors:0 dropped:0 overruns:0 frame:0 > TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:0 (0.0 b) TX bytes:492 (492.0 b) > > eth1 Link encap:Ethernet HWaddr 08:00:27:3C:FB:14 > inet addr:100.1.1.1 Bcast:0.0.0.0 Mask:255.255.255.0 > inet6 addr: fe80::a00:27ff:fe3c:fb14/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:13 errors:0 dropped:0 overruns:0 frame:0 > TX packets:40 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:1398 (1.3 KiB) TX bytes:4103 (4.0 KiB) > > eth2 Link encap:Ethernet HWaddr 08:00:27:5E:7F:83 > BROADCAST MULTICAST MTU:1500 Metric:1 > RX packets:0 errors:0 dropped:0 overruns:0 frame:0 > TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) > 3) brctl addbr br0 ==> created bridge interface > 4) brctl addif br0 eogre ==> attach eogre interface to bridge > 5) brctl addif br0 eth2 ==> attach eth2 interface to bridge > 6) sysctl -w net.ipv6.conf.eth2.disable_ipv6=1 ==> disable ipv6 in eth2 > just to avoid unwanted ipv6 signalling messages from it. > 7) ifconfig eth2 up ==> eth2 iface up with no IP in it yet. > 8) ifconfig eogre up ==> eogre iface up > 9) ifconfig br0 up ==> Bridge up. > 10) brctl show ==> > bridge name bridge id STP enabled interfaces > br0 8000.0800275e7f83 no eogre > > eth2 > > 11) brctl showstp br0 > > [root@centos-dev ~]# brctl showstp br0 > br0 > bridge id 8000.0800275e7f83 > designated root 8000.0800275e7f83 > root port 0 path cost 0 > max age 19.99 bridge max age > 19.99 > hello time 1.99 bridge hello time > 1.99 > forward delay 14.99 bridge forward delay > 14.99 > ageing time 299.95 > hello timer 0.50 tcn timer > 0.00 > topology change timer 0.00 gc timer > 1.50 > hash elasticity 4 hash max 512 > mc last member count 2 mc init query count 2 > mc router 1 mc snooping 1 > mc last member timer 0.99 mc membership timer > 259.96 > mc querier timer 254.96 mc query interval > 124.98 > mc response interval 9.99 mc init query interval > 31.24 > flags > > > eogre (0) > port id 0000 state > forwarding > designated root 8000.0800275e7f83 path cost 100 > designated bridge 8000.0800275e7f83 message age timer > 0.00 > designated port 8001 forward delay timer > 0.00 > designated cost 0 hold timer > 0.00 > mc router 1 > flags > > eth2 (0) > port id 0000 state > forwarding > designated root 8000.0800275e7f83 path cost 4 > designated bridge 8000.0800275e7f83 message age timer > 0.00 > designated port 8002 forward delay timer > 0.00 > designated cost 0 hold timer > 0.00 > mc router 1 > flags > > 12) dhclient -i eth2 ==> This command triggers a DHCP-DISCOVER > broadcast(both l2/l3 broadcast destination addressed) from eth2 and > initiate ip allocation process. > > Now if i capture packets in wireshark in eth1+br0+eogre interface of > Router-1, i don't see the dhcp-discover packet sent from eth2 interface > going over EoGRE Tunnel to Router-2. > But the same DHCP-Discover packet i can see if i capture in eth2 > interface(obvious reason). > > Is it not like whatever packets coming in or originating from eth2 will be > bridged to eogre interface using bridge "br0"? > I am using kernel 2.6 in CentOS > > Can someone please help here? > > Regards, > ...Balaji You can't and shouldn't try to do anything that assigns an IP address to a device that is a member of a bridge. In your case that is eth2. The correct thing to do is run DHCP client on the bridge device.
