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my network has a DHCP server incapable of serving PXE requests (you cannot set next-server option at all) and thist server MUST remain as DHCP server.
I would like to have a PXE booting on the network, but as I said earlier, I cannot do that with this current DHCP server. Is it possible to for example setup secondary DHCP server which would only provide the missing option to PXE clients? Iam opened to any other solution, just please, keep in mind, that I need this current DHCP to stay.
Thanks a lot!
I have found this, so it is possible:
http://danielboca.blogspot.cz/2012/02/boot-linux-from-network-using-pxe-and.html
The part with DNSMASQ is important
In general; no. You're only meant to have one "authoritative" DHCP server per subnet. This is because the client broadcasts a "who am I?" request without knowing who/where the DHCP server is; and the DHCP server is meant to notice this, allocate an IP address from the pool and respond with a "You are ...." reply - if there are 2 DHCP servers they both reply and the client gets all confused.
The easiest way out (other than fixing/replacing the existing DHCP server) may be to create a new subnet, such that packets broadcast on the new subnet don't make it to the existing network (but other traffic does). Then you'd assign a range of IP addresses to the new subnet (and make sure those IP addresses can't be assigned by the old DHCP server), and have a new DHCP server managing that pool of IP addresses for the new subnet.
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On Windows 10 i try to set up a ubuntu server VM with a static IP.
How can i accomplish this ? I heard that i have to use a bridge connection ?
I want the ip of my vm be accessible from my windows session.
Thanks
If you require the guest to be accessible from the local LAN you will need to use the bridged adapter, thus allowing DHCP from the directly connected LAN. (you can take the DHCP address and statically assign it to the guest or do a DHCP reservation)
Another option is to setup a NATNetwork (VirtualBox/Preferences) setup Port Forwarding to allow your VirtualBox host (192.168.56.0/24) to forward tcp/udp to your static assigned guest IP 10.0.2.x/24
Host request
https://192.168.56.x:1234 will be forwarded to your unbuntu guest static IP of 10.0.2.x:443
External request will require routing tables on the remote computer to be added or windows 10 LAN default gateway will require static route for 192.168.56.x/24 via Windows 10 LAN IP, however your host firewall rules will have to configured.
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I have Mikrotik router with Wifi connected to:
WAN/internet on port ether1.
Other ports are for LAN 10.0.1.*.
Only port ether8 is connected to another simple POE switch. Four IP cameras with static IP are connected. This is LAN2 192.168.50.*. Port is not included in bridge or switch.
From main LAN I can access internet and other PC on same LAN, but can't access IP cameras on LAN2.
So, what is wrong/missing in my Mikrotik configuration:
/ip address
add address=10.0.1.1/24 comment="default configuration" interface= ether2-master-local network=10.0.1.0
add address=10.0.0.18/30 interface=ether1-gateway network=10.0.0.16
add address=192.168.50.253/24 interface=ether8-master-local-SUBNET network=
192.168.50.0
/ip route
add distance=2 gateway=10.0.0.17
No ping or trace route can reach LAN2 from main LAN.
If I connect to POE switch with my laptop and configure static IP in range 192.168.50.* than I can access all cameras OK.
If try ping IP camera directly from Mikrotik via ether8 than I get random mix of timeouts and success which is really strange.
Any help is appreciated.
did you set 192.168.50.253 as gateway in your IP cameras ? So they know how to reply to 10.0.1.0/24 when they receive a ping.
As for the random success ping problem, this is weird indeed, maybe an IP conflict (did you try with only 1 camera plugged?)
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I understand that the job of IP in the TCP stack, when dealing with an outgoing message, is to resolve an IP address from a host name and add this address as a header.
Is this process that IP goes through equivalent to using a tool like nslookup for a given hostname?
Your understanding is incorrect. IP doesn't know anything about device names, it only deals with IP addresses.
An application can query a DNS server or a hosts file to resolve a name into an IP address. This must be done prior to using IP to forward a packet since IP can only use an IP address. Tools, like you mention, and other applications, such as browsers, query a DNS server (requires you have the IP address of a DNS server configured) or use a hosts file to resolve the name to an IP address.
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I've got a Draytek Vigor 2820 that's used to connect to the internet. WAN1 is used as an ADSL backup, and WAN2 is our main fibre connection. WAN2 has a total of 6 IP addresses, a single dynamic one and 5 static IPs and is configured up as a PPPoE connection with DynamicIP.
I use NAT Port Redirection to open up some specific ports to various servers (web development, FTP, RDC etc)
I use NAT Open Ports to open up some static IP ports to specific servers
I use NAT Address Mapping to force all traffic received on one static IP to our Exchange server
What I want to do is to force outgoing traffic to use one of the static IPs and have hit a brick wall. Ideally I'd like to force specific traffic but would settle for all!
Under LAN is the ability to configure Static Routes, but this is purely there to allow internal routing (for VLANs).
Anybody else who has this type of router and can give me any suggestions?
OK, managed to work this one out.
Under WAN > Internet Access, select WAN2
On the PPPoE page, change the "Fixed IP" to Yes and enter one of the static IP's into the Fixed IP Address box. Click OK and then reboot the router.
All traffic will now go from that IP address. If you go back to the same page and click WAN IP Alias, the top spot will have the IP address entered in it which will likely be repeated in the list, I just removed the 'double' from the NAT pool and everything seems to work OK.
Sadly there appears to be no way of having all traffic to one IP being sent via one static IP
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Background info:
I have a set of proprietary embedded-linux network devices, one of which will be configured as a DHCP server and the rest will be DHCP clients.
I need to have the client-devices only accept DHCP lease offers from the server-device, ignoring any other leases offered by other DHCP servers on the same LAN. Similarly, I need to make the server-device only serve DHCP requests to this set of clients, ignoring any other DHCP requests which may appear in an unknown network environment. Essentially, I need to be able to provide a DHCP service for my own devices in a network environment which may already have a DHCP server.
All of my devices have the same first half of the MAC address which I intend to use as a filter.
I am using udhcpc and udhcpd which are included in BusyBox and am trying to avoid adding any other DHCP client/server packages to my devices due to limited storage availability, but I am open to modifying BusyBox code.
I had no trouble implementing the DHCP server restrictions by adding an option to udhcpd.conf, which I called chaddr_filter, containing a wildcarded MAC address the server should check the "Client Hardware Address (chaddr)" against. This seems to be working just fine and the server ignores any DHCP requests from other devices while serving my own.
The client-side filtering turns out to be a bigger challenge, due to a lack of a "Server Hardware Address" field in a DHCP packet.
So here's my question:
What's the best way to pass my server's MAC to my udhcpc client?
Currently it looks like there are no fields or options being passed from the DHCP server that contain the server's MAC (doesn't look like I can read it from Ethernet layer). I'd like to remain standards-compliant, so I'm looking through potential DHCP Options which I may use for this purpose.
I was hoping I could use "Option 54: Server identifier", but the RFC defines it as an IP address.
I'm thinking of putting the server's MAC in either "Option 60: Class-identifier" or "Option 43: Vendor specific information", is there a reason I shouldn't do this? Is there a better field for this?
I look forward to any suggestions.
Taken from wikipedia
DHCP uses the same two ports assigned by IANA for BOOTP: destination
UDP port 67 for sending data to the server, and UDP port 68 for data
to the client. DHCP communications are connectionless in nature.
Thus, you could filter on clients the incoming packets on port 68/udp accepting only those coming from a mac address whose first half is good.
FYI I was able to achieve the desired effect by using brctl and ebtables utilities to filter packets of interest on the clients.