xt_TCPMSS:坏长度消息

Question

我收到了很多信息，比如：

Jun 23 10:24:20 awakening kernel: [ 1691.596823] xt_TCPMSS: bad length (1492 bytes)
Jun 23 10:24:21 awakening kernel: [ 1692.663362] xt_TCPMSS: bad length (1448 bytes)
Jun 23 10:24:21 awakening kernel: [ 1692.663495] xt_TCPMSS: bad length (1448 bytes)
Jun 23 10:24:21 awakening kernel: [ 1692.663588] xt_TCPMSS: bad length (1448 bytes)
Jun 23 10:24:21 awakening kernel: [ 1692.663671] xt_TCPMSS: bad length (1440 bytes)
Jun 23 10:24:26 awakening kernel: [ 1697.062914] xt_TCPMSS: bad length (474 bytes)
Jun 23 10:24:26 awakening kernel: [ 1697.305525] xt_TCPMSS: bad length (1492 bytes)
Jun 23 10:24:27 awakening kernel: [ 1698.946633] xt_TCPMSS: bad length (1492 bytes)
Jun 23 10:24:36 awakening kernel: [ 1707.481198] xt_TCPMSS: bad length (1492 bytes)
Jun 23 10:24:37 awakening kernel: [ 1708.723526] xt_TCPMSS: bad length (805 bytes)
Jun 23 10:24:38 awakening kernel: [ 1709.599461] xt_TCPMSS: bad length (805 bytes)
Jun 23 10:24:41 awakening kernel: [ 1712.211052] xt_TCPMSS: bad length (1492 bytes)
Jun 23 10:24:41 awakening kernel: [ 1712.260588] xt_TCPMSS: bad length (1492 bytes)
Jun 23 10:24:41 awakening kernel: [ 1712.976058] xt_TCPMSS: bad length (1492 bytes)
Jun 23 10:24:43 awakening kernel: [ 1714.225209] xt_TCPMSS: bad length (1492 bytes)
Jun 23 10:24:43 awakening kernel: [ 1714.914961] xt_TCPMSS: bad length (1492 bytes)
Jun 23 10:24:55 awakening kernel: [ 1726.192696] xt_TCPMSS: bad length (1480 bytes)
Jun 23 10:24:55 awakening kernel: [ 1726.192825] xt_TCPMSS: bad length (1480 bytes)

在我的dmesg/syslog。这台linux机器是作为互联网网关使用的。连接通过PPPoE。我的iptable脚本中有以下一行：

$IPT -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu # PPPoE fix

当我几天前从Debian的2.6.27升级到2.6.32的时候，这些消息的频率增加了10倍。为什么我会看到这些信息，我如何修复它们呢？

Answer 1

我通过从我的FW脚本中删除TCPMSS行来解决这个问题。显然，PPP系统在建立PPP连接时已经为iptable添加了一行。