There is a problem with fragmented IP packet sent within 802.1Q tagged ethernet frame through bridge. Problem exists when conntrack is enabled (i.e. nf_conntrack_ipv4 module is loaded). Then, such packets are not fragmented again (after prior reassembling on bridge device) during passing it to bridge enslaved NIC. It cause MTU exceeding and as a result dropping packet. Problem exists from kernel version 2.6.17 to 2.6.21.3 inclusive. Below, there is a patch to fix it. Regards. --- linux-2.6.21.3.orig/net/bridge/br_netfilter.c 2007-05-25 09:56:15.000000000 +0200 +++ linux-2.6.21.3/net/bridge/br_netfilter.c 2007-05-25 10:11:42.000000000 +0200 @@ -731,7 +731,7 @@ static int br_nf_dev_queue_xmit(struct sk_buff *skb) { - if (skb->protocol == htons(ETH_P_IP) && + if ((skb->protocol == htons(ETH_P_IP) || IS_VLAN_IP(skb)) && skb->len > skb->dev->mtu && !skb_is_gso(skb)) return ip_fragment(skb, br_dev_queue_push_xmit); _______________________________________________ Bridge mailing list Bridge@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/bridge