I have several PCs/LapTops accessing the Internet through a wireless router (Linksys WRT54G). It also acts as a DHCP server presenting each connected PC with an IP-address. For Internet access it works flawlessly but I have other application which access the PCs on the LAN, such as back-up programs (Bacula).
For the last sort of applications I need to have either a static IP-address or an allways correct association between workstation name and its IP-address (/etc/hosts). It so happens that if the configuration (in terms of connected PCs/LapTops) remains static then the boxes get the same IP-address each time they connect to the router. This is, however, not allways true if the configuration is dynamic (many different PCs and not allways the same).
I feel that what I really need is a DSN on the LAN which is being updated each time a box connects to the router and gets an IP-address. I have noticed that some people disable the DHCP server in their router and establesh a DHCP server in one of connected PCs, but I don't see how that can be accomplished and what happens if that server is taken out of the network?
Is there a way out of this problem?
On Sat, 2006-08-05 at 20:17 +0200, Erik P. Olsen wrote:
I have several PCs/LapTops accessing the Internet through a wireless router (Linksys WRT54G). It also acts as a DHCP server presenting each connected PC with an IP-address. For Internet access it works flawlessly but I have other application which access the PCs on the LAN, such as back-up programs (Bacula).
For the last sort of applications I need to have either a static IP-address or an allways correct association between workstation name and its IP-address (/etc/hosts). It so happens that if the configuration (in terms of connected PCs/LapTops) remains static then the boxes get the same IP-address each time they connect to the router. This is, however, not allways true if the configuration is dynamic (many different PCs and not allways the same).
I feel that what I really need is a DSN on the LAN which is being updated each time a box connects to the router and gets an IP-address. I have noticed that some people disable the DHCP server in their router and establesh a DHCP server in one of connected PCs, but I don't see how that can be accomplished and what happens if that server is taken out of the network?
Is there a way out of this problem?
I'm not sure I understand you correctly, but what about giving this (backup) host a static ip address outside the dhcp range but obviously in the same network ? Just narrow down the dhcp range on the router if necessary.
-- Erik P. Olsen, Civilingeniør, MSc Solsortvej 30, DK-2000 Frederiksberg, Denmark Phone: +45 38346480, Fax: +45 38346470, Mobil: +45 40765300
Eric Donkersloot wrote:
On Sat, 2006-08-05 at 20:17 +0200, Erik P. Olsen wrote:
I have several PCs/LapTops accessing the Internet through a wireless router (Linksys WRT54G). It also acts as a DHCP server presenting each connected PC with an IP-address. For Internet access it works flawlessly but I have other application which access the PCs on the LAN, such as back-up programs (Bacula).
For the last sort of applications I need to have either a static IP-address or an allways correct association between workstation name and its IP-address (/etc/hosts). It so happens that if the configuration (in terms of connected PCs/LapTops) remains static then the boxes get the same IP-address each time they connect to the router. This is, however, not allways true if the configuration is dynamic (many different PCs and not allways the same).
I feel that what I really need is a DSN on the LAN which is being updated each time a box connects to the router and gets an IP-address. I have noticed that some people disable the DHCP server in their router and establesh a DHCP server in one of connected PCs, but I don't see how that can be accomplished and what happens if that server is taken out of the network?
Is there a way out of this problem?
I'm not sure I understand you correctly, but what about giving this (backup) host a static ip address outside the dhcp range but obviously in the same network ? Just narrow down the dhcp range on the router if necessary.
OK. Let me explain it more specific. In the back-up config files I can address the clients (the PCs to be backed up) by either their IP-addresses or their hostnames (I think Windoze calls it workstation names). IP-addresses are dynamic and may change, host names are static so I can enter their host names into the config files to keep them static provided I have a dynamic way of modifying /etc/hosts whenever a box connects to the LAN. /etc/hosts is in a sense a DNS I just don't know of any method to keep it current.
OK. Let me explain it more specific. In the back-up config files I can address the clients (the PCs to be backed up) by either their IP-addresses or their hostnames (I think Windoze calls it workstation names). IP-addresses are dynamic and may change, host names are static so I can enter their host names into the config files to keep them static provided I have a dynamic way of modifying /etc/hosts whenever a box connects to the LAN. /etc/hosts is in a sense a DNS I just don't know of any method to keep it current.
turn off DHCP on the router and setup a DHCP server on the backup server. Then in the dhcpd.conf set it up so that each PC's mac address is configured so they allways get the same IP address. Therefore even though the network is providing DHCP the clients you want to backup allways get the same IP.
Is that what you are after?
thanks
On Sat, 2006-08-05 at 21:00 +0200, Erik P. Olsen wrote:
Eric Donkersloot wrote:
On Sat, 2006-08-05 at 20:17 +0200, Erik P. Olsen wrote:
I have several PCs/LapTops accessing the Internet through a wireless router (Linksys WRT54G). It also acts as a DHCP server presenting each connected PC with an IP-address. For Internet access it works flawlessly but I have other application which access the PCs on the LAN, such as back-up programs (Bacula).
For the last sort of applications I need to have either a static IP-address or an allways correct association between workstation name and its IP-address (/etc/hosts). It so happens that if the configuration (in terms of connected PCs/LapTops) remains static then the boxes get the same IP-address each time they connect to the router. This is, however, not allways true if the configuration is dynamic (many different PCs and not allways the same).
I feel that what I really need is a DSN on the LAN which is being updated each time a box connects to the router and gets an IP-address. I have noticed that some people disable the DHCP server in their router and establesh a DHCP server in one of connected PCs, but I don't see how that can be accomplished and what happens if that server is taken out of the network?
Is there a way out of this problem?
I'm not sure I understand you correctly, but what about giving this (backup) host a static ip address outside the dhcp range but obviously in the same network ? Just narrow down the dhcp range on the router if necessary.
OK. Let me explain it more specific. In the back-up config files I can address the clients (the PCs to be backed up) by either their IP-addresses or their hostnames (I think Windoze calls it workstation names). IP-addresses are dynamic and may change, host names are static so I can enter their host names into the config files to keep them static provided I have a dynamic way of modifying /etc/hosts whenever a box connects to the LAN. /etc/hosts is in a sense a DNS I just don't know of any method to keep it current.
I think the easiest way to solve your problem is to use your router internal dns capability if it has one (I believe yours does). For instance, on my home network, the speedtouch wireless router I use acts as a internal dns server, so machines can find each other through the dns service provide by the router.
-- Erik P. Olsen, Civilingeniør, MSc Solsortvej 30, DK-2000 Frederiksberg, Denmark Phone: +45 38346480, Fax: +45 38346470, Mobil: +45 40765300
On Sat, 2006-08-05 at 14:00, Erik P. Olsen wrote:
I have several PCs/LapTops accessing the Internet through a wireless router (Linksys WRT54G). It also acts as a DHCP server presenting each connected PC with an IP-address. For Internet access it works flawlessly but I have other application which access the PCs on the LAN, such as back-up programs (Bacula).
For the last sort of applications I need to have either a static IP-address or an allways correct association between workstation name and its IP-address (/etc/hosts). It so happens that if the configuration (in terms of connected PCs/LapTops) remains static then the boxes get the same IP-address each time they connect to the router. This is, however, not allways true if the configuration is dynamic (many different PCs and not allways the same).
I feel that what I really need is a DSN on the LAN which is being updated each time a box connects to the router and gets an IP-address. I have noticed that some people disable the DHCP server in their router and establesh a DHCP server in one of connected PCs, but I don't see how that can be accomplished and what happens if that server is taken out of the network?
Is there a way out of this problem?
I'm not sure I understand you correctly, but what about giving this (backup) host a static ip address outside the dhcp range but obviously in the same network ? Just narrow down the dhcp range on the router if necessary.
OK. Let me explain it more specific. In the back-up config files I can address the clients (the PCs to be backed up) by either their IP-addresses or their hostnames (I think Windoze calls it workstation names). IP-addresses are dynamic and may change, host names are static
Errr... I wouldn't call a name that any user can change on a whim "static".
so I can enter their host names into the config files to keep them static provided I have a dynamic way of modifying /etc/hosts whenever a box connects to the LAN. /etc/hosts is in a sense a DNS I just don't know of any method to keep it current.
The best approach to this is to go into the DHCP server and tie the IP addresses it gives out to the specific ethernet MAC addresses of the target PC's so they will always be the same when they are connected to this network. Most DHCP server provide some way to do this. If the PCs never move you can also do static assignments on the client side.
Then if you have enough machines that maintaining host file entries is a problem, set up your own DNS server with a real or fake domain for your LAN.
Also, if the only issue is backups, you might want to look at backuppc: http://backuppc.sourceforge.net/. Among other nice features, it can find windows DHCP targets by their netbios names.
On Sat, 2006-08-05 at 20:17 +0200, Erik P. Olsen wrote:
I feel that what I really need is a DSN on the LAN which is being updated each time a box connects to the router and gets an IP-address. I have noticed that some people disable the DHCP server in their router and establesh a DHCP server in one of connected PCs, but I don't see how that can be accomplished and what happens if that server is taken out of the network?
Well, if the server disappears, I'm sure you can guess what happens. You've got to work out how likely that scenario is. It's also possible to have fall-over backup servers.
How it's accomplished is turning off the DHCP server on your router, there'll be a configuration option somewhere. Then you install and configure a DNS and DHCP server somewhere on one, or more, of your PCs, and configure them to integrate with each other. Which, like many things, is often harder to explain than actually do (there's quite a few webpages around on the WWW about "local DNS and DHCP serving on Fedora", or Linux in general).
Your DHCP server will not only be configured to dole out IPs to your network, it'll also inform those PCs with what addresses to use to get out to the internet through your router (the gateway), etc. PCs connecting to the network will ask to be configured as a broadcast query to anything that listens, and your server will respond.
The simple solution would probably be to configure your router's DHCP server to always dole out the same IP to the same machine. Quite a few have a table that lets you enter NIC MACs to be given a certain IP. But this is more limited than running servers on a PC. e.g. You don't often get a chance to manually set up DNS records for a LAN on a router.
Erik P. Olsen wrote:
I have several PCs/LapTops accessing the Internet through a wireless router (Linksys WRT54G). It also acts as a DHCP server presenting each connected PC with an IP-address. For Internet access it works flawlessly but I have other application which access the PCs on the LAN, such as back-up programs (Bacula).
For the last sort of applications I need to have either a static IP-address or an allways correct association between workstation name and its IP-address (/etc/hosts). It so happens that if the configuration (in terms of connected PCs/LapTops) remains static then the boxes get the same IP-address each time they connect to the router. This is, however, not allways true if the configuration is dynamic (many different PCs and not allways the same).
I feel that what I really need is a DSN on the LAN which is being updated each time a box connects to the router and gets an IP-address. I have noticed that some people disable the DHCP server in their router and establesh a DHCP server in one of connected PCs, but I don't see how that can be accomplished and what happens if that server is taken out of the network?
Is there a way out of this problem?
Thanks a lot to all of you who took the time to respond. I think I have enough ammunition to design a good solution to my problem.
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Eric Donkersloot -
Erik P. Olsen -
Les Mikesell -
Tim -
Tom Brown