[Bridge] challenge of year: connect to LAN using wireless-ap over bridge + unmanaged l2tpv3 tunnel + bridge? it's possible?
Jorge Pereira
jpereiran at gmail.com
Sun Aug 25 23:54:37 UTC 2013
Hi Joel,
thanks for your answer!! but i CAN'T understand why my bridge (SERVER
A) don't forward the arp-request
from LAN to my other side of L2TPv3 (SERVER B).... so, all i need it's
that my 'bridge' forward (broadcast, anycast, unicast, arp, ...)
everything to other side of L2TPv3 bridge... let me try to explain
below...
e.g:
+------------------------------------------------+
| Bahia: lan network 10.251.0.0/16 |
+------------------------------------------------+
|
| +-----------------------------+
+--> | Bridge A |
| LAN: bridge/promisc|
| WAN: 200.199.10.1 |
+---- +-----------------------------+
|
|
\ +--------------------------------------------------------+
+---| L2TPv3 / promisc / l2tpeth0 over WAN |
/ +--------------------------------------------------------+
|
| +-----------------------------+
+--> | Bridge B |
| LAN: bridge/promisc|
| WAN: 200.199.10.2 |
+-----+-----------------------------+
|
+-------------------------------------------------+
| Recife: lan network 10.251.0.0/16 |
+-------------------------------------------------+
e.g - 1: from side 'B', i can send icmp request to anyone in
10.251.0.0/16. but can't receive response because
my bridge A ignore/discard all packets arp/unicast/... and does not
forward to Bridge B. only broadcast!
e.g - 2: (sysct/proxy_arp) don't solves my problem... if somebody have
any suggestion, please! tell me! :)
On Fri, Aug 23, 2013 at 2:22 AM, Joel Wirāmu Pauling <joel at aenertia.net> wrote:
> You can't bridge 802.11 segments with normal ethernet segments. Wifi AP's
> that do this use magic; or hidden pesudo bridges to do the same.
>
> You will need to use something like relayd to form a psuedo bridge between
> your wired and wireless segments or use routing.
>
>
> -Joel
>
>
> On 23 August 2013 14:21, Jorge Pereira <jpereiran at gmail.com> wrote:
>>
>> hi everyone,
>>
>> so,first it seemed a trivial question to me, but since I could not
>> find anybody being neither able to answer
>> this question nor giving a short config example. after a few sleepless
>> nights and exhausting all the reading
>> and research. here I am sharing my problem with all of you, in the hope of
>> some possible solution/sugestion.
>> or is it that this is impossible??
>>
>> below my scheme/layout.
>>
>> +---------------------------------------------------------+
>> | MAIN SERVER - 10.60.61.1 (DHCP SERVER) |
>> +---------------------------------------------------------+
>> |
>> +---------------------------+
>> | NETWORK vlan601 |
>> | net 10.251.0.0/16 |
>> | gw:10.251.0.1 |
>> +---------------------------+
>> |
>> +------------------------------------------------------------------+
>> | SERVER B (BRIDGE / unmanaged L2TPv3) - BAHIA |
>> +------------------------------------------------------------------+
>>
>> root at bahia:~# ip -d addr show eth0 # WAN
>> 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state
>> UP qlen 1000
>> link/ether 00:50:56:a7:13:49 brd ff:ff:ff:ff:ff:ff
>> inet 200.243.1.5/24 brd 200.243.1.255 scope global eth0
>> inet6 fe80::250:56ff:fea7:1349/64 scope link
>> valid_lft forever preferred_lft forever
>> root at bahia:~# ip -d addr show eth1 # LAN (VLAN/TRUNK)
>> 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state
>> UP qlen 1000
>> link/ether 00:50:56:a7:13:4a brd ff:ff:ff:ff:ff:ff
>> inet6 fe80::250:56ff:fea7:134a/64 scope link
>> valid_lft forever preferred_lft forever
>> root at bahia:~# ip link add link eth1 name eth1.601 mtu 1500 type vlan id
>> 601
>> root at bahia:~# ip link set dev eth1.601 up promisc on
>> root at bahia:~# ip -d addr show eth1.601
>> 9: eth1.601 at eth1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc
>> noqueue state UP
>> link/ether 00:50:56:a7:13:4a brd ff:ff:ff:ff:ff:ff
>> inet6 fe80::250:56ff:fea7:134a/64 scope link
>> valid_lft forever preferred_lft forever
>> root at bahia:~# ip route show
>> default via 200.243.1.254 dev eth0
>> 200.243.1.0/24 dev eth0 proto kernel scope link src 200.243.1.5
>> root at bahia:~#
>>
>> and.... we've the interface l2tpeth0 (L2TPv3) established with other node
>> into the internet by eth0 (WAN), plugged
>> with vlan601 (eth1.601) by bridge called "br-red"
>>
>> root at bahia:~# brctl show
>> bridge name bridge id STP enabled interfaces
>> root at bahia:~# brctl addbr br-red
>> root at bahia:~# brctl addif br-red eth1.601
>> root at bahia:~# ip l2tp add tunnel tunnel_id 45 peer_tunnel_id 42 udp_sport
>> 5001 udp_dport 5000 encap udp local 200.243.1.5 remote 200.199.10.12
>> root at bahia:~# ip l2tp add session tunnel_id 45 session_id 5196755
>> peer_session_id 128
>> root at bahia:~# ip link set l2tpeth0 up promisc on master br-red
>> root at bahia:~# ip link set br-red up
>> root at bahia:~# brctl show br-red
>> bridge name bridge id STP enabled interfaces
>> br-red 8000.005056a7134a no eth1.601
>> l2tpeth0
>> root at bahia:~# brctl showstp br-red
>> br-red
>> bridge id 8000.005056a7134a
>> designated root 8000.005056a7134a
>> root port 0 path cost 0
>> max age 20.00 bridge max age 20.00
>> hello time 2.00 bridge hello time 2.00
>> forward delay 15.00 bridge forward delay 15.00
>> ageing time 300.01
>> hello timer 1.06 tcn timer 0.00
>> topology change timer 0.00 gc timer 5.08
>> flags
>>
>> eth1.601 (1)
>> port id 8001 state forwarding
>> designated root 8000.005056a7134a path cost 4
>> designated bridge 8000.005056a7134a message age timer 0.00
>> designated port 8001 forward delay timer 0.00
>> designated cost 0 hold timer 0.06
>> flags
>>
>> l2tpeth0 (2)
>> port id 8002 state forwarding
>> designated root 8000.005056a7134a path cost 100
>> designated bridge 8000.005056a7134a message age timer 0.00
>> designated port 8002 forward delay timer 0.00
>> designated cost 0 hold timer 0.05
>> flags
>>
>> root at bahia:~#
>>
>> it's ok, my bridge "by-red" listen all traffic over my LAN (vlan 601) and
>> my L2TPv3 over internet. (wan)
>>
>> root at bahia:~# tcpdump -nve -i br-red "host 10.251.0.1"
>> tcpdump: WARNING: br-red: no IPv4 address assigned
>> tcpdump: listening on br-red, link-type EN10MB (Ethernet), capture size
>> 65535 bytes
>> 20:58:17.860060 d4:ae:52:84:37:ae > ff:ff:ff:ff:ff:ff, ethertype ARP
>> (0x0806), length 60: Ethernet (len 6), IPv4 (len 4), Request who-has
>> 10.251.90.157 tell 10.251.0.1, length 46
>> 20:58:17.980065 d4:ae:52:84:37:ae > ff:ff:ff:ff:ff:ff, ethertype ARP
>> (0x0806), length 60: Ethernet (len 6), IPv4 (len 4), Request who-has
>> 10.251.153.31 tell 10.251.0.1, length 46
>> ^C
>> 7 packets captured
>> 7 packets received by filter
>> 0 packets dropped by kernel
>> root at bahia:~#
>>
>>
>> +-----------------------------------------------------------------------------------------+
>> | SERVER B (BRIDGE/L2TPv3 + WIRELESS ACCESS POINT) - RECIFE |
>>
>> +-----------------------------------------------------------------------------------------+
>>
>> root at recife:~# ip addr show eth1 # (WAN)
>> 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state
>> UP qlen 1000
>> link/ether a0:f3:c1:a3:c4:11 brd ff:ff:ff:ff:ff:ff
>> inet 200.199.10.12/21 brd 200.199.10.255 scope global eth1
>> valid_lft forever preferred_lft forever
>> inet6 fe80::a2f3:c1ff:fea3:c411/64 scope link
>> valid_lft forever preferred_lft forever
>> root at recife:~# ip route show
>> default via 200.199.10.254 dev eth1 proto static
>> 200.199.10.0/21 dev eth1 proto kernel scope link src 200.199.10.12
>> 192.168.1.0/24 dev br-lan proto kernel scope link src 192.168.1.1
>> root at recife:~# ip l2tp add tunnel tunnel_id 42 peer_tunnel_id 45 udp_sport
>> 5000 udp_dport 5001 encap udp local 200.199.10.12 remote 200.243.1.5
>> root at recife:~# ip l2tp add session tunnel_id 42 session_id 128
>> peer_session_id 5196755
>> root at recife:~# ip link set dev l2tpeth0 up promisc on master br-red
>> root at recife:~# brctl show
>> bridge name bridge id STP enabled interfaces
>> br-lan 7fff.a0f3c1a3c40f no eth0
>> root at recife:~# brctl addbr br-red
>> root at recife:~# brctl addif br-red l2tpeth0
>> root at recife:~# brctl addif br-red wlan0
>> root at recife:~# ifconfig br-red up
>> root at recife:~# ip link set br-red up
>> root at recife:~# brctl show
>> bridge name bridge id STP enabled interfaces
>> br-lan 7fff.a0f3c1a3c40f no eth0
>> br-red 8000.1ae0f4a30221 no l2tpeth0
>>
>> wlan0
>> root at recife:~#
>>
>> ....::: RESUME :::...
>>
>> 1) sorry for the long email....
>> 2) when i'm "recife hostspot"... I can join in wireless "Recife Wireless"
>> from my device, but i can't receive ip from dhcp (10.60.61.1).
>> 3) from "server A[bahia] (bridge with vlan601 network) and "server B
>> [recife]", i can "see/listen" the broadcast request from my
>> device mac "5c:95:ae:22:d6:6e" like below.
>>
>> root at bahia:~# tcpdump -nve -i br-red "ether host ether 5c:95:ae:22:d6:6e"
>> 00:08:52.653667 5c:95:ae:22:d6:6e > ff:ff:ff:ff:ff:ff, ethertype IPv4
>> (0x0800), length 342: (tos 0x0, ttl 255, id 37839, offset 0, flags [none],
>> proto UDP (17), length 328)
>> 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from
>> 5c:95:ae:22:d6:6e, length 300, xid 0xe6f1d0a5, Flags [none]
>> Client-Ethernet-Address 5c:95:ae:22:d6:6e
>> Vendor-rfc1048 Extensions
>> Magic Cookie 0x63825363
>> DHCP-Message Option 53, length 1: Discover
>> Parameter-Request Option 55, length 6:
>> Subnet-Mask, Default-Gateway, Domain-Name-Server,
>> Domain-Name
>> Option 119, Option 252
>> MSZ Option 57, length 2: 1500
>> Client-ID Option 61, length 7: ether 5c:95:ae:22:d6:6e
>> Lease-Time Option 51, length 4: 7776000
>> Hostname Option 12, length 14: "Straces-iPhone"
>> ^C
>> 1 packets captured
>> 1 packets received by filter
>> root at bahia:~#
>>
>> same thing result at "bridge a" (root at recife:~#) side...
>>
>> 4) the strangest thing of all and that, from bridge-b (recife). i can get
>> ip from dhcp/broadcast request over L2TPv3...
>> but without option "broadcast" i can't receive ip from dhcp (10.61.60.1)
>>
>> root at recife:~# udhcpc -B -i br-red
>> udhcpc (v1.19.4) started
>> Sending discover...
>> Sending select for 10.251.157.22...
>> Lease of 10.251.157.22 obtained, lease time 300
>> udhcpc: ifconfig br-red 10.251.157.22 netmask 255.255.0.0 broadcast +
>> udhcpc: setting default routers: 10.251.0.1
>> root at recife:~# ip route add 200.243.1.5 via 200.199.10.254 dev eth1
>> root at recife:~# ip route show
>> default via 10.251.0.1 dev br-red
>> 10.251.0.0/16 dev br-red proto kernel scope link src 10.251.157.22
>> 200.199.10.0/21 dev eth1 proto kernel scope link src 200.199.10.12
>> 200.243.1.5 via 200.199.10.254 dev eth1
>> 192.168.1.0/24 dev br-lan proto kernel scope link src 192.168.1.1
>> root at recife:~# ping -c2 10.251.0.1
>> PING 10.251.0.1 (10.251.0.1): 56 data bytes
>>
>> --- 10.251.0.1 ping statistics ---
>> 2 packets transmitted, 0 packets received, 100% packet loss
>> root at recife:~#
>>
>> 5) output of tcpdump listen the bridge "br-red" request from
>> bridge-a-natal http://pastebin.com/t8wn3zRK
>> 6) output of tcpdump listen the bridge "br-red" request from
>> bridge-b-recife http://pastebin.com/njTQfd5k
>> 7) after several researches i found the kernel options to set like
>> "arp_filter", "bridge-nf-*",... but i don't have
>> idea which option should enable / disable. tried some combinations but
>> without success....
>> 8) the DHCP-OFFER doesn't forward by "bridge-a"... problems with unicast?
>> multicast? arp_proxy? ....
>> 9) we need join in the network by wireless and access the server
>> 10.251.0.1 over bridge/l2tpv3 (unmanaged)
>> 10) in our case, can use only L2TPv3. (may not be OpenVPN, ...)
>> 11) all is Linux, without any iptables rules.
>> 12) who will win a beer?! =]
>>
>> Best regards,
>> Jorge Pereira
>
>
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