Re: OT: Bridging ADSL

MTUroute is your friend for working with MTU issues. The same can be
accomplished via CLI or even a Linux shell, but this tool just makes it
faster and more visual.

http://www.elifulkerson.com/projects/mturoute.php

On Thu, Feb 17, 2011 at 3:38 PM, Paul Cocker <paul.cocker_at_gmx.com> wrote:

> no joy. i guess that it really needs to work in both directions, so even
> if they get fragmented on the way out on the inside device, it would come
> back as a whole packet and need fragmenting on the way back in again (for a
> ping that is)
>
> i'll maybe get wireshark on it and take a look at some point.
>
>
> On 17/02/2011 20:43, Carlos G Mendioroz wrote:
>
>> Hey Paul,
>> glad it worked out. You may want to reduce the ASA MTU in case
>> your CPE is not doing the fragments (ASA should, I guess :)
>>
>> -Carlos
>>
>> Paul Cocker @ 17/02/2011 17:37 -0300 dixit:
>>
>>> hi Carlos,
>>>
>>> looked into a bit more and apparently you can use pppoA or pppoE, so I
>>> tried pppoe and seemed to get it working. only problem is one of the routers
>>> seems to refuse to fragment packets now, which is a bit odd (I have adjusted
>>> the mtu to take account of the larger ppp packets).
>>>
>>> for any interested readers, below is the basic config to get the assigned
>>> IP from the telco onto another router.
>>>
>>> Paul
>>>
>>>
>>>
>>> ------------------------
>>> PPPOE client
>>> !
>>> vpdn enable
>>> vpdn-group 1
>>> !
>>> interface GigabitEthernet0/1
>>> no ip address
>>> duplex auto
>>> speed auto
>>> pppoe enable group global
>>> pppoe-client dial-pool-number 1
>>>
>>> int gig0/0
>>> desc inside
>>> ip tcp adjust-mss 1452
>>> ip address ..
>>> !
>>> interface Dialer0
>>> mtu 1492
>>> ip tcp adjust-mss 1452
>>> ip address negotiated
>>> ip flow ingress
>>> ip nat outside
>>> ip virtual-reassembly
>>> encapsulation ppp
>>> dialer pool 1
>>> dialer-group 1
>>> no cdp enable
>>> ppp authentication chap callin
>>> ppp chap hostname xxxxxxxxx_at_hg39.btclick.com
>>> ppp chap password 7 xxxxxxxxxxxxxxxxxxx
>>> ppp ipcp dns request accept
>>> !
>>> ip route 0.0.0.0 0.0.0.0 Dialer0
>>>
>>> ---------------------------------------
>>>
>>> hostname bridging_router
>>>
>>> bridge irb
>>> !
>>> interface ATM0
>>> no ip address
>>> no atm ilmi-keepalive
>>> pvc 0/38
>>> encapsulation aal5snap
>>> !
>>> dsl operating-mode auto
>>> bridge-group 1
>>> !
>>> interface FastEthernet3
>>> switchport access vlan 1
>>>
>>> interface Vlan1
>>> bridge-group 1
>>> !
>>> bridge 1 protocol ieee
>>> bridge 1 route ip
>>> !
>>>
>>> On 11/02/2011 20:25, Paul Cocker wrote:
>>>
>>>> Hi Carlos,
>>>>
>>>> At home it's just standard ADSL, not ATM. I don't really understand why
>>>> you don't need the dialer interface for it.
>>>>
>>>> Afraid the other ISP is PPPoA not PPPoE
>>>>
>>>> Thanks for your input,
>>>> Paul
>>>>
>>>>
>>>>
>>>> On 11/02/2011 10:53, Carlos G Mendioroz wrote:
>>>>
>>>>> Paul,
>>>>> at home it seems you are getting IP over ATM.
>>>>> But now, with the dialer interface, you might be using PPPoA or PPPoE.
>>>>> In the first case, I guess you are OOL.
>>>>> If PPPoE, you could bridge at the CPE and terminate the pppoe link
>>>>> directly at the ASA.
>>>>>
>>>>>
>>>>> http://www.cisco.com/en/US/products/ps6120/products_configuration_example09186a0080ab7ce9.shtml
>>>>>
>>>>> -Carlos
>>>>>
>>>>>
>>>>> Paul Cocker @ 10/02/2011 15:22 -0300 dixit:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> Sort of off topic, but interesting to me :-) I wonder if anyone has
>>>>>> any experience of this.
>>>>>>
>>>>>> At home i like to run an ASA with the real outside address, so I use
>>>>>> this setup to bridge the ATM interface to the ethernet. The ASA then just
>>>>>> picks up an IP with DHCP. I also get a 2nd IP off the BVI interface. My ISP
>>>>>> doesn't require PPP.
>>>>>>
>>>>>> ----------------------------------------------
>>>>>> bridge irb
>>>>>> bridge 5 protocol ieee
>>>>>> bridge 5 route ip
>>>>>>
>>>>>> !
>>>>>> interface ATM0
>>>>>> no ip address
>>>>>> no atm ilmi-keepalive
>>>>>> !
>>>>>> interface ATM0.1 point-to-point
>>>>>> ip virtual-reassembly in
>>>>>> atm route-bridged ip
>>>>>> bridge-group 5
>>>>>> pvc 0/101
>>>>>> encapsulation aal5snap
>>>>>>
>>>>>> interface FastEthernet8
>>>>>> description link to ASA outside - bridging ATM
>>>>>> switchport access vlan 5
>>>>>>
>>>>>> interface Vlan5
>>>>>> description bridge group for internet
>>>>>> no ip address
>>>>>> bridge-group 5
>>>>>>
>>>>>> interface BVI5
>>>>>> ip address dhcp
>>>>>> ip flow ingress
>>>>>> ip nat outside
>>>>>> ip virtual-reassembly in
>>>>>>
>>>>>> ----------------------------------------------
>>>>>>
>>>>>>
>>>>>> That all seems to work ok, hoever I've tried to do it with another ISP
>>>>>> that requires a dialer interface for the ADSL, in line with this doc from
>>>>>> cisco which is about bridging ISDN...
>>>>>>
>>>>>>
>>>>>> http://www.cisco.com/en/US/tech/tk801/tk379/technologies_configuration_example09186a008009457f.shtml
>>>>>>
>>>>>> Now. I guess dhcp isn't going to work on the PC/ASA attached to the
>>>>>> fastethernet interface as DHCP ain't the same as PPP IP negotiate.
>>>>>>
>>>>>> Anyone see a way to make this work? Maybe if the ISP provided a static
>>>>>> IP?
>>>>>>
>>>>>> A bit weird I know, and more for fun than anything else. Any ideas?
>>>>>>
>>>>>> Paul
>>>>>>
>>>>>>
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>>>>>
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>>>
>
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Received on Fri Feb 18 2011 - 11:10:36 ART