All of lore.kernel.org
 help / color / mirror / Atom feed
* [Bridge] Bridge interface not forwarding DHCP-Broadcast
@ 2016-12-13 15:43 Balaji J
  2016-12-13 17:41 ` Stephen Hemminger
  0 siblings, 1 reply; 6+ messages in thread
From: Balaji J @ 2016-12-13 15:43 UTC (permalink / raw)
  To: bridge

[-- Attachment #1: Type: text/plain, Size: 5199 bytes --]

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

[-- Attachment #2: Type: text/html, Size: 7632 bytes --]

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [Bridge] Bridge interface not forwarding DHCP-Broadcast
  2016-12-13 15:43 [Bridge] Bridge interface not forwarding DHCP-Broadcast Balaji J
@ 2016-12-13 17:41 ` Stephen Hemminger
  2016-12-13 18:15   ` Balaji J
  0 siblings, 1 reply; 6+ messages in thread
From: Stephen Hemminger @ 2016-12-13 17:41 UTC (permalink / raw)
  To: Balaji J; +Cc: bridge

On Tue, 13 Dec 2016 21:13:43 +0530
Balaji J <ping2balaji@gmail.com> 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.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [Bridge] Bridge interface not forwarding DHCP-Broadcast
  2016-12-13 17:41 ` Stephen Hemminger
@ 2016-12-13 18:15   ` Balaji J
  2016-12-13 19:16     ` Stephen Hemminger
  0 siblings, 1 reply; 6+ messages in thread
From: Balaji J @ 2016-12-13 18:15 UTC (permalink / raw)
  To: Stephen Hemminger; +Cc: bridge

[-- Attachment #1: Type: text/plain, Size: 6991 bytes --]

Thanks Stephen.
Can i attach an interface with IP assigned to it already/statically to a
bridge?
So if i understand correctly from your response, i should run dhcpclient on
br0 interface to assign IP for the same? and Lets say br0 gets an IP
assigned by DHCP-Server as "12.0.0.1".

Now my intention is to assign IP address to the Host(say host1) behind
Router-1 using the DHCP-Server running on/behind Router-2 as shown below:
Host1 <------> (eth2)[Router-1](eth1:100.1.1.1) <----------EoGRE
Tunnel----->(eth0:100.1.1.254)[Router-2](DHCP-Server)

So i thought Bridging eth2 to eth1 in Router-1 is the only way to achieve
the same as i want the dhcp-broadcast packet from Host-1 to get tunneled
over EogRE till Router-2. Is this assumption correct? or i am missing
something here?

Or i should not assign any IP to eth2 and instead do it in br0 in Router-1?

Any guidance would be very helpful and greatly appreciated.

Thanks,
...Balaji.J



On Tue, Dec 13, 2016 at 11:11 PM, Stephen Hemminger <
stephen@networkplumber.org> wrote:

> On Tue, 13 Dec 2016 21:13:43 +0530
> Balaji J <ping2balaji@gmail.com> 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.
>

[-- Attachment #2: Type: text/html, Size: 9899 bytes --]

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [Bridge] Bridge interface not forwarding DHCP-Broadcast
  2016-12-13 18:15   ` Balaji J
@ 2016-12-13 19:16     ` Stephen Hemminger
  2016-12-14  2:03       ` Balaji J
  0 siblings, 1 reply; 6+ messages in thread
From: Stephen Hemminger @ 2016-12-13 19:16 UTC (permalink / raw)
  To: Balaji J; +Cc: bridge

On Tue, 13 Dec 2016 23:45:52 +0530
Balaji J <ping2balaji@gmail.com> wrote:

> Thanks Stephen.
> Can i attach an interface with IP assigned to it already/statically to a
> bridge?
> So if i understand correctly from your response, i should run dhcpclient on
> br0 interface to assign IP for the same? and Lets say br0 gets an IP
> assigned by DHCP-Server as "12.0.0.1".
> 
> Now my intention is to assign IP address to the Host(say host1) behind
> Router-1 using the DHCP-Server running on/behind Router-2 as shown below:
> Host1 <------> (eth2)[Router-1](eth1:100.1.1.1) <----------EoGRE
> Tunnel----->(eth0:100.1.1.254)[Router-2](DHCP-Server)
> 
> So i thought Bridging eth2 to eth1 in Router-1 is the only way to achieve
> the same as i want the dhcp-broadcast packet from Host-1 to get tunneled
> over EogRE till Router-2. Is this assumption correct? or i am missing
> something here?
> 
> Or i should not assign any IP to eth2 and instead do it in br0 in Router-1?
> 
> Any guidance would be very helpful and greatly appreciated.
> 
> Thanks,
> ...Balaji.J

The problem is that the IP address on an enslaved interface is not used
by the IP stack and packets destined for that address tend to be blackholed.
Packets being sent out get put on the enslaved interface and only sent
out that interface not bridged.


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [Bridge] Bridge interface not forwarding DHCP-Broadcast
  2016-12-13 19:16     ` Stephen Hemminger
@ 2016-12-14  2:03       ` Balaji J
  2016-12-14  8:01         ` Srinivas M.A.
  0 siblings, 1 reply; 6+ messages in thread
From: Balaji J @ 2016-12-14  2:03 UTC (permalink / raw)
  To: Stephen Hemminger; +Cc: bridge

[-- Attachment #1: Type: text/plain, Size: 2831 bytes --]

Thanks Stephen.

In the following article it is quoted that dhclient can be run on the
interface attached to the bridge:
https://wiki.linuxfoundation.org/networking/bridge

So does it not mean against what you have mentioned below?
"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."
i have tried to do the same like this as below:
--> brctl addif br0 eth2
--> dhclient eth2

Quoting from the link:
"
Does DHCP work over/through a bridge?

The bridge will forward DHCP traffic (broadcasts) and responses. You can
also use DHCP to set the local IP address of the bridge pseudo-interface.

One common mistake is that the default bridge forwarding delay setting is
30 seconds. This means that for the first 30 seconds after an interface
joins a bridge, it won't send anything. This is because if the bridge is
being used in a complex topology, it needs to discover other bridges and
not create loops. This problem was one of the reasons for the creation of
Rapid Spanning Tree Protocol (RSTP).

If the bridge is being used standalone (no other bridges near by). Then it
is safe to turn the forwarding delay off (set it to zero), before adding
interface to a bridge. Then you can run DHCP client right away.

 # brctl setfd br0 0
 # brctl addif br0 eth0
 # dhclient eth0

"


On Wed, Dec 14, 2016 at 12:46 AM, Stephen Hemminger <
stephen@networkplumber.org> wrote:

> On Tue, 13 Dec 2016 23:45:52 +0530
> Balaji J <ping2balaji@gmail.com> wrote:
>
> > Thanks Stephen.
> > Can i attach an interface with IP assigned to it already/statically to a
> > bridge?
> > So if i understand correctly from your response, i should run dhcpclient
> on
> > br0 interface to assign IP for the same? and Lets say br0 gets an IP
> > assigned by DHCP-Server as "12.0.0.1".
> >
> > Now my intention is to assign IP address to the Host(say host1) behind
> > Router-1 using the DHCP-Server running on/behind Router-2 as shown below:
> > Host1 <------> (eth2)[Router-1](eth1:100.1.1.1) <----------EoGRE
> > Tunnel----->(eth0:100.1.1.254)[Router-2](DHCP-Server)
> >
> > So i thought Bridging eth2 to eth1 in Router-1 is the only way to achieve
> > the same as i want the dhcp-broadcast packet from Host-1 to get tunneled
> > over EogRE till Router-2. Is this assumption correct? or i am missing
> > something here?
> >
> > Or i should not assign any IP to eth2 and instead do it in br0 in
> Router-1?
> >
> > Any guidance would be very helpful and greatly appreciated.
> >
> > Thanks,
> > ...Balaji.J
>
> The problem is that the IP address on an enslaved interface is not used
> by the IP stack and packets destined for that address tend to be
> blackholed.
> Packets being sent out get put on the enslaved interface and only sent
> out that interface not bridged.
>
>

[-- Attachment #2: Type: text/html, Size: 4640 bytes --]

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [Bridge] Bridge interface not forwarding DHCP-Broadcast
  2016-12-14  2:03       ` Balaji J
@ 2016-12-14  8:01         ` Srinivas M.A.
  0 siblings, 0 replies; 6+ messages in thread
From: Srinivas M.A. @ 2016-12-14  8:01 UTC (permalink / raw)
  To: Balaji J; +Cc: bridge

On Wed, Dec 14, 2016 at 7:33 AM, Balaji J <ping2balaji@gmail.com> wrote:

> In the following article it is quoted that dhclient can be run on the
> interface attached to the bridge:
> https://wiki.linuxfoundation.org/networking/bridge

>  # brctl setfd br0 0
>  # brctl addif br0 eth0
>  # dhclient eth0

This seems like a typo. It should be "dhclient br0" just like the
"dhclient mybridge" in an example further up in the page.

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2016-12-14  8:01 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-12-13 15:43 [Bridge] Bridge interface not forwarding DHCP-Broadcast Balaji J
2016-12-13 17:41 ` Stephen Hemminger
2016-12-13 18:15   ` Balaji J
2016-12-13 19:16     ` Stephen Hemminger
2016-12-14  2:03       ` Balaji J
2016-12-14  8:01         ` Srinivas M.A.

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.