Obviously I'm letting my first experience with this provider using a beta
version of Mikrotik Router OS affect my troubleshooting methodology.
I didn't realise that I was getting lots of PPPoE dropouts on the link I'm
having problems with and using Astlinux on my other service works fine so its
not an MTU/MSS issue.
And I realised in my testing that I was not taking the overhead into account.
The PPPoE MTU setting is 1492 which includes the 28 Byte MTU header. So
1492-28=1464 which is what I was getting with the ping test which is the
payload only!
Anyway thanks for your help Lonnie. Sorry to stuff you around.
Regards
Michael Knill
On 26/6/20, 12:40 pm, "Lonnie Abelbeck" <li...@lonnie.abelbeck.com> wrote:
Or in the same /tmp/etc/ppp/pppoe.conf file add:
--
MTU=1452
MRU=1452
--
and leave PPPD_EXTRA alone.
Lonnie
> On Jun 25, 2020, at 9:19 PM, Lonnie Abelbeck <li...@lonnie.abelbeck.com>
wrote:
>
> Hi Michael,
>
> Looking at the code, to make the MTU stick would require some script
changes, but you could test...
>
> After boot edit /tmp/etc/ppp/pppoe.conf
>
> You should see something like:
>
> PPPD_EXTRA="persist maxfail 0"
>
> You should be able to add pppd options to that, something like:
>
> PPPD_EXTRA="persist maxfail 0 mtu 1452 mru 1452"
>
> (Or try 1460)
>
> Then restart PPPoE.
>
> (Note 1452 is 1412+40)
>
> If that works we could add a rc.conf variable to add the mtu/mru options.
>
> Lonnie
>
>
>
>
>> On Jun 25, 2020, at 8:56 PM, Michael Knill
<michael.kn...@ipcsolutions.com.au> wrote:
>>
>> Thanks Lonnie
>>
>> Hmm MSS should be fine then assuming it is working.
>> I will do some more testing on the new service in my home office.
Unfortunately the one not working is a building site and its way too cold at
the moment.
>>
>> Regards
>> Michael Knill
>>
>> On 26/6/20, 11:45 am, "Lonnie Abelbeck" <li...@lonnie.abelbeck.com>
wrote:
>>
>>
>>
>>> On Jun 25, 2020, at 8:05 PM, Michael Knill
<michael.kn...@ipcsolutions.com.au> wrote:
>>>
>>> Hi Group
>>>
>>> I have changed my internet provider and I am having connectivity
problems to some sites on Astlinux.
>>> I am fairly certain that it is an MTU/MSS issue as I have fixed it on
my Mikrotik router by adjusting this value.
>>> Funny that I'm having problems with this provider but not on my
previous provider. Both are using PPPoE and I tested that the maximum MTU for
both is 1464 e.g.
>>>
>>> 3035-JSainsbury-CM1 kd # fping -M -b 1465 12000.ipcaccess.net
>>> 12000.ipcaccess.net: error while sending ping: Message too long
>>> 3035-JSainsbury-CM1 kd # fping -M -b 1464 12000.ipcaccess.net
>>> 12000.ipcaccess.net is alive
>>>
>>> 3076-VisionCF-CM1 kd # fping -M -b 1465 12000.ipcaccess.net
>>> 12000.ipcaccess.net: error while sending ping: Message too long
>>> 3076-VisionCF-CM1 kd # fping -M -b 1464 12000.ipcaccess.net
>>> 12000.ipcaccess.net is alive
>>>
>>> Maybe my new provider is not allowing fragmentation?
>>>
>>> Anyway just wondering how I fix this problem. Do I just set MTU using
IFMTU in user.conf? E.g.
>>> IFMTU=ppp0:1460
>>
>> No, per the /stat/etc/rc.conf file:
>> --
>> ## MTU Changes
>> ## If you need to specifically set the MTU for a given interface, do
that here.
>> ## You can try to set the MTU for any valid type of interface. With
ethernet it
>> ## works most of the time. Everything else, caveat emptor...
>> ## If you are using PPPoE don't worry. We automatically handle those
MTU issues
>> #IFMTU="eth2.41:1496 eth0:1492"
>> --
>>
>> I don't see any configuration for the PPPoE MTU, though there may be a
way.
>>
>> What is the local MTU set to by default ?
>> --
>> ip link show dev ppp0
>> --
>>
>> After the PPPoE link is up you could try to change it:
>> --
>> ip link set dev ppp0 mtu 1460
>> --
>>
>> If that works we can try to figure out how to make that stick.
>>
>>
>>> Can I set the TCP MSS anywhere?
>>
>> This is the current value hardcoded in the PPPoE config:
>>
>> CLAMPMSS=1412
>> -- PPPoE docs --
>> CLAMPMSS
>> The value at which to "clamp" the advertised MSS for TCP sessions. The
default of 1412 should be fine.
>> --
>>
>> Lonnie
>>
>>
>>
>>
>>
>>>
>>> Regards
>>> Michael Knill
>>> _______________________________________________
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>>> https://lists.sourceforge.net/lists/listinfo/astlinux-users
>>>
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pay...@krisk.org.
>>
>>
>>
>> _______________________________________________
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>>
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pay...@krisk.org.
>>
>>
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>>
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pay...@krisk.org.
>
>
>
> _______________________________________________
> Astlinux-users mailing list
> Astlinux-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/astlinux-users
>
> Donations to support AstLinux are graciously accepted via PayPal to
pay...@krisk.org.
_______________________________________________
Astlinux-users mailing list
Astlinux-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/astlinux-users
Donations to support AstLinux are graciously accepted via PayPal to
pay...@krisk.org.
_______________________________________________
Astlinux-users mailing list
Astlinux-users@lists.sourceforge.net
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Donations to support AstLinux are graciously accepted via PayPal to
pay...@krisk.org.
