* iptables-1.2.9, kernel-2.6.0, pppd-2.4.2
@ 2003-12-31 7:37 zhang ping
2003-12-31 12:03 ` Antony Stone
2003-12-31 23:03 ` Mark E. Donaldson
0 siblings, 2 replies; 3+ messages in thread
From: zhang ping @ 2003-12-31 7:37 UTC (permalink / raw)
To: netfilter
----adsl----linuxbox----lan
pppd-2.4.2 (use kernel mode pppoe)
iptables-1.2.9
kernel-2.6.0
when I visit www.zaobao.com at lan, it is ok, but I cant visit
www.kernel.org, so qi guai.
when i set mtu as 1300 at lan, everthins is ok, i can visit all sites.
what is the matter, anybody help me?
_________________________________________________________________
享用世界上最大的电子邮件系统― MSN Hotmail。 http://www.hotmail.com
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: iptables-1.2.9, kernel-2.6.0, pppd-2.4.2
2003-12-31 7:37 iptables-1.2.9, kernel-2.6.0, pppd-2.4.2 zhang ping
@ 2003-12-31 12:03 ` Antony Stone
2003-12-31 23:03 ` Mark E. Donaldson
1 sibling, 0 replies; 3+ messages in thread
From: Antony Stone @ 2003-12-31 12:03 UTC (permalink / raw)
To: netfilter
On Wednesday 31 December 2003 7:37 am, zhang ping wrote:
> ----adsl----linuxbox----lan
>
> pppd-2.4.2 (use kernel mode pppoe)
> iptables-1.2.9
> kernel-2.6.0
>
> when I visit www.zaobao.com at lan, it is ok, but I cant visit
> www.kernel.org, so qi guai.
>
> when i set mtu as 1300 at lan, everthins is ok, i can visit all sites.
>
> what is the matter, anybody help me?
This problem has been known for a long time. You need to clamp the MTU on
your interface to the Maximum Segment Size supported by your ADSL link.
http://lists.netfilter.org/pipermail/netfilter/2003-November/048409.html
Antony.
--
Anyone that's normal doesn't really achieve much.
- Mark Blair, Australian rocket engineer
Please reply to the list;
please don't CC me.
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: iptables-1.2.9, kernel-2.6.0, pppd-2.4.2
2003-12-31 7:37 iptables-1.2.9, kernel-2.6.0, pppd-2.4.2 zhang ping
2003-12-31 12:03 ` Antony Stone
@ 2003-12-31 23:03 ` Mark E. Donaldson
1 sibling, 0 replies; 3+ messages in thread
From: Mark E. Donaldson @ 2003-12-31 23:03 UTC (permalink / raw)
To: 'zhang ping', netfilter
Nothing is the matter. You're packets destined to (or coming from) zaobao
are taking one route, and you're packets to kernel are taking a different
route. The difference is, the packets to kernel are going through a router
that supports an MTU of less than 1500. Thus, fragmentation is required.
However, a router somewhere along this path more than likely contains an ACL
that drops ICMP Type 3 Code 4 Fragmentation Required but DF set) packets.
Consequently, your system is never notified of the need to reduce the MTU,
and all packets are dropped. By reducing your MTU to 1300, you have
circumvented the need for fragmentation, and traffic flow to Kernel goes
undisturbed and uninterrupted.
-----Original Message-----
From: netfilter-admin@lists.netfilter.org
[mailto:netfilter-admin@lists.netfilter.org] On Behalf Of zhang ping
Sent: Tuesday, December 30, 2003 11:38 PM
To: netfilter@lists.netfilter.org
Subject: iptables-1.2.9, kernel-2.6.0, pppd-2.4.2
----adsl----linuxbox----lan
pppd-2.4.2 (use kernel mode pppoe)
iptables-1.2.9
kernel-2.6.0
when I visit www.zaobao.com at lan, it is ok, but I cant visit
www.kernel.org, so qi guai.
when i set mtu as 1300 at lan, everthins is ok, i can visit all sites.
what is the matter, anybody help me?
_________________________________________________________________
享用世界上最大的电子邮件系统― MSN Hotmail。 http://www.hotmail.com
^ permalink raw reply [flat|nested] 3+ messages in thread
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2003-12-31 7:37 iptables-1.2.9, kernel-2.6.0, pppd-2.4.2 zhang ping
2003-12-31 12:03 ` Antony Stone
2003-12-31 23:03 ` Mark E. Donaldson
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