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4

ARP only works on the same LAN (layer-2 broadcast domain) because an ARP request is a broadcast. Broadcasts do not cross a layer-3 boundary. MAC addresses are layer-2 addresses, and they are only significant, or even seen, on the same layer-2 broadcast domain. A host wishing to send traffic to a different layer-3 network will send the traffic to the layer-2 ...


3

My personal recommendation would be to use NIC teaming, for a number of reasons. NIC teaming/boding will allow for link redundancy and/or load balancing, depending on which options you select and your hardware/OS choices. If you opt for a load-balanced configuration, traffic will be split across both links, effectively giving you a single, logical 2Gbps "...


3

Try using a 6in4 tunnel broker to get IPv6 connectivity. It is more reliable and will work in this case. The brokers I am aware of offer free tunnels. The upgrade is quick and relatively painless. I've been using 6in4 over with IPv6 on eth0 for years.


3

Yes, there are many differences between alias and vlan: VLANs are isolated When you're using IP alias, you're just propaging new IP on same network. It can be from same subnet or from different one. But anyone who can join to your LAN can access both subnets just adding new IP to their PC. You cannot manage it and secure it. Also anyone can listen to your ...


3

You have to add route to 123.4.5.6 trought your ISP gate. For example: route add -host 123.4.5.6 gw 192.168.0.1 According your Linux distribution put this rule for routing in appropriate config file.


2

It looks like you are running a newer OpenSSH client (OpenSSH 7.2p2) against an older OpenSSH server (OpenSSH 6.6.1p1). In the OpenSSH 7.1p2 release notes, it mentions: ssh(1), sshd(8): increase the minimum modulus size supported for diffie-hellman-group-exchange to 2048 bits. From the error message reported, it looks like it is your client ...


2

You should be able to find the source by checking the MAC addresses embeded in the data "44 a8 12 41 1d 2b 13 8b 9c ab 34 89 10 00". 44:a8:12:41:1d:2b should be your interface's MAC address. 13:8b:9c:ab:34:89 should be the remote device's MAC address. Try checking your cache to see if you have any other addresses for those MAC addresses. arp -a should be ...


2

Much of the problems experienced with martian source is caused by network topography considerations. The following may need to be addressed: Router: The router may be routing through illegal addresses; make sure that the router is configured correctly. Multiple NICS: If a computer has multiple NIC cards plugged in to the same switch, then ...


2

It looks like you miss either range definition or a specific host entry for those boxes, matching their MACs. Unless your failing boxes are on the list that "goes on like this", they won't have any address assigned.


2

You can actually do this, but you'll need to use the NF_LOG iptables target and write a program that specifically covers your needs. NF_LOG will send packets to a receiving application which (given how quickly you manage to do what you are doing) would count the packets are a per-millisecond level. You can avoid writing out every packet doing this and ...


1

It turns out it is a routing problem on the switch. Multicast routing for the VLAN in 10.1.1.x is not turned on. Once we added 'pim sparse-mode' on our cisco router. Everything is working as expected.


1

I was certain I didn't do anything to cause this issue, but it was my VPS provider after all. I just needed to click on the rebuild network button to get it working again.


1

ServerName is not the directive you want to set. Listen should be on all interfaces and maybe test specific with: (Listen 192.168.21.128:80) as well as you want: <VirtualHost *:80> VM's IP is 192.168.21.128 - is it from the host-bridge-adapter or corporate-dhcp? Anyway if you can successfully telnet 192.168.21.128 80 your browser will do too. ...


1

If you have users that have root access to the machine, they can do anything they want. Any measures you put in place to prevent enabling of the NIC could be trivially worked around. So your options are: Don't give root access to users on this system. Instead, broker what privileged commands they can use with sudo. Sort out another way to disable/enable ...


1

The issue was caused by the DDoS protection software from the datacenter. It contained a bug which caused big latency for DNS lookups. I reinstalled the OS, disabled the DDoS protection (they're fixing the bug) and everything is working now.


1

For the first question: does an "allow member" statement implicitly deny everything else ? The question is answered in the manpage of dhcpd.conf: If a pool has a permit list, then only those clients that match specific entries on the permit list will be eligible to be assigned addresses from the pool. If a pool has a deny list, then only those clients ...


1

Cumulus Networks has upstreamed their patch to set the speed on the virtio_net driver. It is useful in network simulations with their Cumulus VX VM product. Patch is in Ubuntu Xenial. not sure if it is in Fedora today. More details can be found here. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1581132 Another reference is my blog post about why ...


1

Is there a way to do a 1-to-1 NAT in IPv6 (I'm using Linux machine as a router)? This is known as "network prefix translation" and yes linux does support it. You use the "SNPT" and "DNPT" targets in the "mangle" table (the "nat" table is only used for stateful NAT). How do I do it? You use the SNPT target to change the source prefix on outgoing ...



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