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Date:      Thu, 26 Dec 2002 08:23:59 -0800 (PST)
From:      Rostislav Krasny <rosti_bsd@yahoo.com>
To:        stacey@vickiandstacey.com
Cc:        freebsd-net@freebsd.org, FreeBSD Questions <freebsd-questions@FreeBSD.ORG>
Subject:   Re: PPPoE and troubles with TCP
Message-ID:  <20021226162359.78406.qmail@web14804.mail.yahoo.com>
In-Reply-To: <1040916764.68500.54.camel@localhost>

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--- Stacey Roberts <stacey@vickiandstacey.com> wrote:
> On Thu, 2002-12-26 at 14:41, Rostislav Krasny wrote:
> > --- Stacey Roberts <stacey@vickiandstacey.com> wrote:
> > > On Thu, 2002-12-26 at 13:16, Rostislav Krasny wrote:
> > > > --- Stacey Roberts <stacey@vickiandstacey.com> wrote:
> > > > > On Thu, 2002-12-26 at 12:26, Rostislav Krasny wrote:
> > > > > > Hello
> > > > > > 
> > > > > > I have Alcatel Speedtouch Home ADSL modem. I use PPPoE protocol
> for
> > > > > > connection with my Internet Service Provider (ISP) through this
> > > ADSL
> > > > > > modem. I use FreeBSD 4.7-RELEASE and ppp (a.k.a. user-ppp) for
> > > this. In
> > > > > > the /etc/ppp/ppp.conf file I have ' set MRU 1492' and ' set MTU
> > > 1492'
> > > > > > options. This is because the maximum MTU one can use with PPPoE
> is
> > > 1492
> > > > > > according to RFC 2516. I have no problems with "dialing" to my
> ISP.
> > > But
> > > > > > after the PPPoE connection is established I have troubles with
> TCP
> > > > > > connections to some hosts. For example I can't go to
> > > > > > hhtp://www.ssh.com/  but to http://www.freebsd.org/ or
> > > > > > http://www.gnu.org/ I can. If I run 'telnet www.ssh.com 80' and
> > > enter
> > > > > > HTTP request according to HTTP 1.1 or 1.0 protocol I don't get
> any
> > > > > > answer. If I enter just 'GET /' I get some short answer. 'GET
> /' is
> > > an
> > > > > > HTTP request according to the old HTTP 0.9 version of the
> protocol
> > > and
> > > > > > it is rarely used today. 
> 
> > <snipped>
> 
> > > > Many lines of the "default:" section of the ppp.conf file are not
> > > critical.
> > > > The only ones you need are these:
> > > > 
> > > >         set device      PPPoE:ed0
> > > >         set MRU         maximum 1492
> > > >         set MTU         maximum 1492
> > > >         enable          dns
> > > > 
> > > > See `man 8 ppp` for more information.
> > > > 
> > > 
> > > Dude,
> > >     I wasn't asking for assistance.., rather I was hoping to provide
> > > some help in response to your post.. :-)
> > > 
> > > The reason why I asked about how you connect to your ADSL modem is
> > > because if its ethernet, then there is no need to use ppp.
> > > 
> > > But if there's a case-requirement why you need to use ppp, then fair
> > > enough.
> > > 
> > > Let me know either way, okay?
> > 
> > Yes, my computer is connected to my ADSL modem by Ethernet.
> > What is the way to connect with the ISP without PPP?
> > Is it ethernet bridging with DHCP? My ADSL Service Provider (Bezeq)
> > does not support this. Moreover, the use of ethernet bridging is
> > inconvenient for me because I can't switch the ISP by myself.
> > When I use PPP, over Ethernet or over whatever else, I have ISP string,
> > so it is very easy to switch the ISP I'd like to use at the moment.
> > 
> > P.S. What about my main question?
> > 
> 
> Hi,
>   I didn't really have to configure *anything* as such to establish
> connectivity on FreeBSD. The router I have holds the configurations
> requried in order to authenticate to the ISP's upstream router.
>
> All I have to do from FreeBSD's view is configure the external interface
> to use the router as the default route (using ifconfig or
> /stand/sysinstall). That's it.

So, your FreeBSD box is within your LAN and have do dial with ADSL at all,
only your router have. Your box have internal LAN's IP 192.168.1.8 and
your router configured to do network address and port translation.
This network configuration is completely different from my one.
I have a modem, not a router.

> As your initial problems, what happens if you set mtu to 1500 (or *not*
> define this?)? Here's what man ppp says:
>  set mtu [max[imum]] [value]
>              The default MTU is 1500.  At negotiation time, ppp will
> accept
>              whatever MRU the peer requests (assuming it's not less than
> 296
>              bytes or greater than the assigned maximum).  If the MTU is
> set,
>              ppp will not accept MRU values less than value.  When
> negotia-
>              tions are complete, the MTU is used when writing to the
> inter-
>              face, even if the peer requested a higher value MRU.  This
> can be
>              useful for limiting your packet size (giving better
> bandwidth
>              sharing at the expense of more header data).
> 
>              If the ``maximum'' keyword is used, ppp will refuse to
> negotiate
>              a higher value.  The maximum MTU can be set to 2048 at
> most.
> 
>              If no value is given, 1500, or whatever the peer asks for
> is
>              used.  A value must be given when ``maximum'' is specified.
> 
> 
>  What does ifconfig ed0 return? Please post that output here.

This is a copy/paste of just 'ifconfig', so you can see all the interfaces:

ed0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet6 fe80::200:21ff:fe82:2503%ed0 prefixlen 64 scopeid 0x1
        ether 00:00:21:82:25:03
faith0: flags=8002<BROADCAST,MULTICAST> mtu 1500
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
        inet6 ::1 prefixlen 128
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
        inet 127.0.0.1 netmask 0xff000000
ppp0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1492
        inet 192.117.108.59 --> 192.117.122.11 netmask 0xffffffff
        Opened by PID 142

I don't use ed0 directly, ppp use it for ppp0. ed0 is like /dev/cuaa1
when you have regular modem, 33600bps one for example. I use tun0 that
support TCP/IP and have MTU == 1492. Read RFC 2516 for information about
the maximum MTU that is correct with PPPoE protocol. 1492 is the maximum.

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