Re: Netfilter(MASQ) and PPPoE problem? (2.4.17)

Daniel Bunzendahl (daniel.bunzendahl@pyramid.de)
Wed, 30 Jan 2002 10:30:08 +0100


Hello Malcolm,
try to change the MTU on your clientmashines:
ifconfig eth0 mtu 1400

then connect again ...

this Problem comes with many Webservers use Loadbalancing and BigIP
because they answer with an different Packetsice and Providers like
T-Online
block this ...

bye


Malcolm Mallardi wrote:

> Heyla, folks. I've got an interesting little report for y'all,
>was hoping to get a bit more insight, 'cause I'm rather stumped on it,
>and can't really make heads or tails of it. I've got a DSL with PPPoE
>set up on the router (running 2.4.17, with NAT) and seem to be having
>problems getting to web sites from client machines behind the firewall.
>
> What makes it so curious is that this happens with only a
>selection of web servers out there, though the number for me seems to be
>growing, unfortunately.
> When I use Lynx from the router, I can get to any site out
>there on the Internet that I choose. My fire walling rules are simple:
>Accepts everything incoming, and outgoing, and masquerades anything
>going out from the LAN to the world beyond through the interfaces of
>ppp0 and ppp1 (ppp0 being the PPPoE interface through eth1, ppp1 being
>the 'backup' dial-up service.)
> The other curious thing is when I route traffic to a troubled
>site through the modem interface (ppp1), I can access things just fine.
>
> After wading through some packet captures targeting this
>problem, I've noticed that when sending a request from one of the
>machines behind the NAT box, the standard handshake is processed, then
>the HTTP get is sent, and the connection is dropped immediately, but
>from the NAT box itself, there's an ACK sent, then the Web server sends
>the information with a HTTP/200 response.
>
> I've been trying to puzzle this out for weeks, and due to all
>the mitigating factors, the only theory that I can come up with is a
>possible bug in the interaction between MASQ and PPPoE, as switching to
>the straight PPP account works just fine.
>
>--
>Malcolm D. Mallardi - Dark Freak At Large
>"Captain, we are receiving two-hundred eighty-five THOUSAND hails."
>AOL: Nuark UIN: 11084092 Y!: Magamo Jabber: Nuark@jabber.com
>http://ranka.2y.net:3000/~magamo/index.htm
>-
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