tcpdump showed me there are some ICMP-redirect in my network (KVM virtual-machines, bridged network). I decided to take a closer look on them and how my system behaves and how it looks. I found it doesn't work as it should: Let say I'm on 1.1.1.1 and I ping 2.2.2.2: # ping 2.2.2.2 PING 2.2.2.2 (2.2.2.2) 56(84) bytes of data. 64 bytes from 2.2.2.2: icmp_seq=1 ttl=63 time=0.569 ms From 4.4.4.4
From 192.168.1.10: icmp_seq=3 Redirect Network(New nexthop: 192.168.1.1) 当时第一的反应是不会是192.168.1.10 出现了什么arp病毒之类的，但下面这台机器不好找，只好在这台机器移除网络，但结果还是 … Linux-Net Archive: Re: ping gives "Redirect Host > >From 3640-1e.site2site.net (208.34.16.121): Redirect Host(New nexthop: > as5248-1e.site2site.net (208.34.16.120)) Again it thinks you are routing to the wrong box.-To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.rutgers.edu. Ubuntu Networking :: "Redirect Host" In Ping Messages?
> From 192.9.200.20: Redirect Host(New nexthop: 192.168.1.10) > 64 bytes from 192.168.1.10: icmp_seq=0 ttl=127 time=4.5 ms > 64 bytes from 192.168.1.10: icmp_seq=1 ttl=127 time=1.5 ms
From 198.50.241.115 icmp_seq=1 Destination Host Unreachable From 198.50.241.115 icmp_seq=2 Destination Host Unreachable --- 192.99.46.254 ping statistics --- 2 packets transmitted, 0 received, +2 errors, 100% packet loss, time 1011ms pipe 2 It responds to redirect the host and then after than the host in unreachable. From 192.168.1.254: icmp_seq=4 Redirect Host(New nexthop: 192.168.1.254) I have another VLAN (VLAN25), but that VLAN is only in the router (not in the switch). Ping from the PC in the VLAN200 to a PC in the VLAN25: I could reproduce the ICMP-redirect-issue on a -not interconnected- vpn-server and the cause of it was not allowing client-to-client traffic. Therefore packets between 2 clients needs to be routed via the host and the host sends it back into the tun-interface. This causes the ICMP-redirect.
Sometimes an ICMP request may go to a peer switch; as a result, the peer switch sends ICMP redirect messages. This occurs in a VRR active-active topology (VRR and Host-MLAG), when the host pings any of the bridge IP addresses, because both links are active. For example: cumulus@host2$ ping 12.0.1.2 PING 12.0.1.2 (12.0.1.2) 56(84) bytes of data.
From 10.XX.0.10 icmp_seq=2 Redirect Host(New nexthop: 10.XX.0.11) 64 bytes from 10.XX.0.11: icmp_seq=2 ttl=128 time=0.617 ms ^C--- 10.XX.0.11 ping statistics ---2 packets transmitted, 2 received, +2 errors, 0% packet lost, time 1001ms. rtt min/avg/max/mdev = 0.617/1113/1.609/0.496 ms. Problems with routing between VLAN's us - Cisco Community From 192.168.1.254: icmp_seq=2 Redirect Host(New nexthop: 192.168.1.254) From 192.168.1.254: icmp_seq=3 Redirect Host(New nexthop: 192.168.1.254) From 192.168.1.254: icmp_seq=4 Redirect Host(New nexthop: 192.168.1.254) I have another VLAN (VLAN25), but that VLAN is only in the router (not in the switch). Ping from the PC in the VLAN200 to a PC