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17

There are two things you need: First you need an ISP that will act as the sponsoring LIR for you. Their role is just book keeping and maintaining the contractual chain between you and RIPE NCC. Then you'll need an ISP that will route your addresses and announce them to the rest of the world using BGP. Those two functions can be provided by a single ISP ...


15

A single anycast IP address does not give you the same redundancy as two unicast IP addresses in distinct IP prefixes would. Often the hardest problem for redundancy is not when something fails completely, but rather when it is misbehaving just enough to still pass the health checks, but not actually be functional. I have seen an anycast DNS setup where a ...


14

The route command is deprecated, and should not be used anymore. The new way is to use the iproute set of commands, which are all invoked with ip followed by an object. For example: $ ip route show default via 192.168.1.254 dev eth0 192.168.0.0/23 dev eth0 proto kernel scope link src 192.168.1.27 Now, I hear you say, this is basically the same info! ...


8

Blocking outbound connections to destination TCP port 25 is something that a lot of ISPs do today. While I don't particularly like it, it's a pretty typical thing that gets done. So long as you publish to your users that you're making this change, and perhaps take some packet captures to pre-emptively see who might be effected by the change, I think it's ...


8

Without further details it's difficult to give an appropriate answer. In the simplest case, with everything on the same IP subnet (including router2's clients), same VLAN, dynamic IP attribution, etc., i.e. the routers can communicate directly without any special switching/routing configuration, all you need is cabling and: set router1 as default gateway ...


7

The routes metric is to set preference among routes with equal specificity. That is true of routing in general (i.e. Cisco, Windows, etc). So the model works like: Find the most specific route (aka the longest prefix match*) If there are multiple routes with the same specificity, pick the one with the lowest administrative distance (This distinguishes ...


7

You must create a default vhost configuration file and include it before of others. For example you can save this default config to /etc/nginx/conf/default.conf: server { listen 80 default_server; return 444; } And include it in nginx.conf: http { .... include "/etc/nginx/conf/default.conf"; include "/etc/nginx/vhosts/*.conf"; } Be sure ...


6

No, you can't do that on the host directly. You need a VM to handle the routing. ESX is not a router.


5

Short answer: No Longer answer: A router which implements just the router functionality does not and cannot verify UDP and TCP checksums. However routers do exist with additional functionality. If the router has NAT and/or firewall functionality, the answer may differ. There are many reasons for a router not to verify the checksums: It would slow down ...


5

Since your question isn't spesific for any OS, I'll answer in some general way too. This can be done two ways: legacy way: you distinguish the processes by uid they run as, and for each specific uid you install specific packet filter rules that forward the traffic as you want. To different gateways, for example. modern way: you bind each process to a ...


5

Userspace routing can be achieved by pointing a default route at a tun device, and having a userspace program examine each received packet. It's an inefficient and brittle approach, but it has been made to work — there was an AODVv2 implementation that worked that way, due to Henning Rogge. The other option, of course, is to implement your routing protocol ...


5

Netfilter (iptables) has queue module to send frames to a userspace program. Libraries for different languages (c, python, perl, etc...) are available to examine packets. After processing a frame you will return an ACCEPT or DROP verdict, the original or modified frame, and an option to set a mark. My guess that you can use the mark to handle this packet ...


4

Set a route to the payment processor via the dedicated IP. The ip route add command is your friend.


4

In RedHat Entrprise Linux 7.0 (the "upstream" of CentOS 7.0) the intended interaction with iptables is through firewalld. Manually modifying the iptables configuration, while possible, is not the intended method if interaction. If you do want to modify the iptables configuration directly you might want to have a look at documentation about iptables. You're ...


4

VLANs have nothing to do with your IP addressing scheme. You're conflating layer 2 and layer 3. At the risk of shamelessly plugging myself I'll suggest you have a look at "How do VLANs work?" and "Best way to segment traffic, Vlan or subnet" (and maybe also "Network: Many subnets in 1 VLAN =? possible"). As a "quick fix": Assuming you're using ...


4

Best practice is to use at least two addresses from different prefixes and giving them a name under two different TLDs. Both those addresses can be anycast if you want. Having only one IP address will give you a single point of failure. If the routing to that address doesn't work (configuration error, an anycast instance not working correctly, the prefix ...


4

There is a simple fix for this, at least when it comes to the most popular Cisco routers: mls cef maximum-routes ip 768 This requires a reboot. Also see Cisco's documentation about adjusting the TCAM to allocate more IPv4 space (and less IPv6): ...


4

What you are describing is what happens when a switch's CAM table is full, where it can no longer learn MAC address and it forwards packets out every port. It might be hard to figure out if this is the problem with an unmanaged switch, but with a managed switch you should be able to display the CAM table. What also would help in this question is a diagram ...


4

You want policy-based routing. Quick distro-agnostic example: echo 200 custom >> /etc/iproute2/rt_tables ip rule add from 192.168.1.8 lookup custom ip route add default via 10.76.8.50 dev eth0 table custom


4

Ok, this can be done, but it's definitely not as easy as it could (and should) be. Basically, the trick is using Azure's "local networks" to configure Azure gateways as we want, even if we can't directly touch their configuration. In order to set up a connection between two Azure virtual networks, you need to define two matching "local networks", and then ...


3

You'll need to use ACLs. Also make sure "ip routing" is enabled in your config. See the HP Advanced Traffic Management Guide. Can you share the model(s) of the switches involved? ip access-list extended "SecureVLAN20-30" 10 permit ip 192.168.20.0 0.0.0.255 192.168.30.0 0.0.0.255 20 permit ip 192.168.30.0 0.0.0.255 192.168.20.0 0.0.0.255


3

First of all: the iptables -A command add the new rule after the end of your actual chains. They were processed only after the last rule in your chains. But it won't happen, because the last rule already filters everything out! You need to put these commands before your last rule, which can be done with the -I <n> flag of the iptables. Second: ...


3

Add the following to your command: route -p add 46.137.226.16 mask 255.255.255.255 10.20.1.1 METRIC 1 IF ## Where ## is the relevant interface number from the top of "Route Print" : Assigning a metric 1 ensures that this will should always be the default route for this IP.


3

SOLVED IT!! My drive was mapped with "\computername\share" which means that it will look for "computername" in the default gateway's subnet, right? When i mapped the drive with "\172.x.x.x\share" it worked! Of course without default gateway and the static route "route add 172.0.0.0 mask 255.0.0.0 172.21.61.161 metric 1 if 11" I can't belive that i missed ...


3

The RFC 1034 only states that you require two DNS servers. This isn't a mandatory requirement, but a recommendation, so do with it what you will. Regardless, if you want HA, your 2 DNS servers can be assigned the same IP using anycast, and the only thing your end users would notice when one DNS server fails, is a momentary lack of connectivity as the network ...


3

If you look at the iproute2 gitweb, you'll see it's showing the status of the RTN_ANYCAST bit set on the kernel routing structure. If you cross-reference that with the kernel source (rtnetlink.h) you'll see the following comment: RTN_ANYCAST, /* Accept locally as broadcast, but send as unicast */ If you check ...


3

Due to the fact that both links have the same IP gateway, you must set in some way the interface you want to use in your routing tables. The syntax is the following: gateway=[ip]%[interface] + specific preferred source; given this fact, in your router these routes should look like the following: /ip route gateway=109.60.164.1%gateway1 pref-src ...


3

10.8.2.12 sees 10.8.2.254 as being on the same subnet, therefore it's requesting the MAC address of 10.8.2.254 to insert it as a dest MAC in future packets to 10.8.2.254. Since 10.8.2.254 doesn't exist, no one is replying and 10.8.2.12 never finds out what MAC to set as the dest MAC. Try using proxy_arp on your main server. echo 1 > ...


3

DHCP is a broadcast protocol you cannot forward (there is no destination IP on another network). What you need is an IP Helper showing to the DHCP Server (the router has to work as a DHCP Relay Agent, transforming the broadcast into a unicast).


3

Seeing a the route "hop around" on your network is really bizarre. You should see a traffic flow that hops form your edge router through your distribution routers. You definitely shouldn't be seeing traffic being routed through end user Customer addresses / devices. I tend to think you're seeing some kind of artifact of your configuration in these traceroute ...



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