Re: [Nagios-users] check_dhcp seems not working
Thank you. But I have neither firewall nor SELinux enabled. In deed for a moment worked, but a couple of hours later it didn't work again. It's really weird. - Mensaje original De: Kevin Keane subscript...@kkeane.com CC: nagios-users@lists.sourceforge.net Enviado: jueves, 15 de enero, 2009 21:55:07 Asunto: Re: [Nagios-users] check_dhcp seems not working Thank you! In my case, the server-side firewall works without a problem. The server does hand out DHCP addresses all the time. It was the client-side firewall (i.e., the one on the Nagios server) that blocked the DHCP request, even though I opened both ports 67 and 68 for both TCP and UDP. It happened both with broadcast DHCP requests and with directed ones (using the -s serverip arg). Oddly enough, I didn't see anything at all in the firewall log that would indicate what was blocked. James Miller wrote: Sorry for the top post 1. Lease Request - The client sends a broadcast requesting an IP address 2. Lease Offer - The server sends the above information and marks the offered address as unavailable. The message sent is a DHCPOFFER broadcast message. 3. Lease Acceptance - The first offer received by the client is accepted. The acceptance is sent from the client as a broadcast (DHCPREQUEST message) including the IP address of the DNS server that sent the accepted offer. Other DHCP servers retract their offers and mark the offered address as available and the accepted address as unavailable. 4. Server lease acknowledgement - The server sends a DHCPACK or a DHCPNACK if an unavailable address was requested. All DHCP packets travel as UDP datagrams; all client-sent packets have source port 68 and destination port 67; all server-sent packets have source port 67 and destination port 68. For example, a server-side firewall should allow the following types of packets: * Incoming packets from 0.0.0.0 or dhcp-pool to dhcp-ip * Incoming packets from any address to 255.255.255.255 * Outgoing packets from dhcp-ip to dhcp-pool or 255.255.255.255 where dhcp-ip represents any address configured on a DHCP server host and dhcp-pool stands for the pool from which a DHCP server assigns addresses to clients Jim Kevin Keane wrote: Christian, actually, your question prompted me to try it again. Turned out that it was the firewall software on my Nagios box that blocked the DHCP request. As soon as I turned it off, check_dhcp worked. I'm not yet sure which ports to open to make it work with the firewall on. So far, I tried ports 67 and 68 for both TCP and UDP, but that seems not to be enough. Christian Iñiguez wrote: Exactly Kevin, you are right - Mensaje original De: Kevin Keane subscript...@kkeane.com CC: nagios-users@lists.sourceforge.net Enviado: jueves, 15 de enero, 2009 13:39:47 Asunto: Re: [Nagios-users] check_dhcp seems not working jmose...@corp.xanadoo.com wrote: Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: Hi Everyone I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. The command line is: check_dhcp -s serverip -t 30 What am I doing wrong? Any suggest? Thanks in advance! I have no idea which flavor of DHCP you are running (probably ISC's), but I don't think you are going to be able to run check_dhcp from the DHCP server itself. The DHCP server will see an incoming requeset from itself and probably block it. Therefore, using the nrpe method of doing these checks is a moot point. If your Nagios server is on the same network as the DHCP server, just run check_dhcp from the Nagios box. If you're running Nagios on a different network than the DHCP server and there is a firewall in between, you'll probably have to do several things: 1. Open up a hole in the firewall to allow the Nagios server to request a DHCP address from the DHCP server 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to 3. Setup a small DHCP subnet on the DHCP server in the same IP range as the Nagios server so it can offer a valid IP address I actually have the same problem as Christian, and it does NOT work even though Nagios is running on a different box on the same network as the DHCP server. In fact, the Nagios box actually gets its IP address from the same DHCP server that I would like to monitor (ISC DHCP server 3.0.6 on a SuSE 10.3). I've seen the same problem before against a Windows DHCP server, too, never been able to make check_dhcp work. check_dhcp -v
Re: [Nagios-users] check_dhcp seems not working
Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: Thank you. But I have neither firewall nor SELinux enabled. In deed for a moment worked, but a couple of hours later it didn't work again. It's really weird. Have you checked your DHCP logs? Do you have enough leases available in the subnet you would expect the Nagios server to be offered an address from? If your DHCP server doesn't hand out DHCP addresses to other machines on that network (the same your Nagios server is on), for the ISC DHCP daemon to even work, you still must define a subnet on that local network in the DHCP config, even if you only have one DHCP address available. This isn't really a Nagios problem, but a problem with check_dhcp. It sounds like the plugin is setup with the appropriate permissions (owned by root, setuid root, etc) and that there are no inbound/outbound firewalls or SELinux issues to deal with. Honestly, unless there is a configuration problem with DHCP, I can't think of anything else. James -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: Hi Everyone I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. The command line is: check_dhcp -s serverip -t 30 What am I doing wrong? Any suggest? Thanks in advance! I have no idea which flavor of DHCP you are running (probably ISC's), but I don't think you are going to be able to run check_dhcp from the DHCP server itself. The DHCP server will see an incoming requeset from itself and probably block it. Therefore, using the nrpe method of doing these checks is a moot point. If your Nagios server is on the same network as the DHCP server, just run check_dhcp from the Nagios box. If you're running Nagios on a different network than the DHCP server and there is a firewall in between, you'll probably have to do several things: 1. Open up a hole in the firewall to allow the Nagios server to request a DHCP address from the DHCP server 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to 3. Setup a small DHCP subnet on the DHCP server in the same IP range as the Nagios server so it can offer a valid IP address There are probably other methods as well. James -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
In deed both servers (the dhcp server and nagios server) are in the same subnet and there is no firewall between them. From the nagios server I run check_nrpe!check_dhcp And in the side of dhcp server I run the command: check_dhcp -s ip_dhcp_server -t 30 Actually I'm running other services like check_load, check_procs, etc. With no problems. Just check_dhcp is not working My dhcp server is a RHEL 5 with dhcp-3.0.5-3.el5 I hope this help! - Mensaje original De: jmose...@corp.xanadoo.com jmose...@corp.xanadoo.com Para: Christian Iñiguez challenger_jos...@yahoo.com.mx CC: nagios-users@lists.sourceforge.net Enviado: jueves, 15 de enero, 2009 13:06:21 Asunto: Re: [Nagios-users] check_dhcp seems not working Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: Hi Everyone I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. The command line is: check_dhcp -s serverip -t 30 What am I doing wrong? Any suggest? Thanks in advance! I have no idea which flavor of DHCP you are running (probably ISC's), but I don't think you are going to be able to run check_dhcp from the DHCP server itself. The DHCP server will see an incoming requeset from itself and probably block it. Therefore, using the nrpe method of doing these checks is a moot point. If your Nagios server is on the same network as the DHCP server, just run check_dhcp from the Nagios box. If you're running Nagios on a different network than the DHCP server and there is a firewall in between, you'll probably have to do several things: 1. Open up a hole in the firewall to allow the Nagios server to request a DHCP address from the DHCP server 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to 3. Setup a small DHCP subnet on the DHCP server in the same IP range as the Nagios server so it can offer a valid IP address There are probably other methods as well. James __ Correo Yahoo! Espacio para todos tus mensajes, antivirus y antispam ¡gratis! Regístrate ya - http://correo.yahoo.com.mx/ -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. The command line is: check_dhcp -s serverip -t 30 What am I doing wrong? Any suggest? This one's come up a billion times or so on the list, but the most likely cause of your problem is that the plugin needs to be setuid root. -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
Thanks but actually the plugin is setuid root, and as user root and user nagios the outcome is the same =( - Mensaje original De: Morris, Patrick patrick.mor...@hp.com Para: Christian Iñiguez challenger_jos...@yahoo.com.mx; nagios-users@lists.sourceforge.net nagios-users@lists.sourceforge.net Enviado: jueves, 15 de enero, 2009 13:18:08 Asunto: RE: [Nagios-users] check_dhcp seems not working I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. The command line is: check_dhcp -s serverip -t 30 What am I doing wrong? Any suggest? This one's come up a billion times or so on the list, but the most likely cause of your problem is that the plugin needs to be setuid root. __ Correo Yahoo! Espacio para todos tus mensajes, antivirus y antispam ¡gratis! Regístrate ya - http://correo.yahoo.com.mx/ -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
James Moseley Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: In deed both servers (the dhcp server and nagios server) are in the same subnet and there is no firewall between them. From the nagios server I run check_nrpe!check_dhcp And in the side of dhcp server I run the command: check_dhcp -s ip_dhcp_server -t 30 Actually I'm running other services like check_load, check_procs, etc. With no problems. Just check_dhcp is not working My dhcp server is a RHEL 5 with dhcp-3.0.5-3.el5 In my previous reply, I told you that what you are trying to do above will *not* work. Do not try and check your DHCP server from the Nagios server using check_nrpe and running check_dhcp on the DHCP server itself. Run check_dhcp directly from the Nagios server. James -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
jmose...@corp.xanadoo.com wrote: Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: Hi Everyone I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. The command line is: check_dhcp -s serverip -t 30 What am I doing wrong? Any suggest? Thanks in advance! I have no idea which flavor of DHCP you are running (probably ISC's), but I don't think you are going to be able to run check_dhcp from the DHCP server itself. The DHCP server will see an incoming requeset from itself and probably block it. Therefore, using the nrpe method of doing these checks is a moot point. If your Nagios server is on the same network as the DHCP server, just run check_dhcp from the Nagios box. If you're running Nagios on a different network than the DHCP server and there is a firewall in between, you'll probably have to do several things: 1. Open up a hole in the firewall to allow the Nagios server to request a DHCP address from the DHCP server 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to 3. Setup a small DHCP subnet on the DHCP server in the same IP range as the Nagios server so it can offer a valid IP address I actually have the same problem as Christian, and it does NOT work even though Nagios is running on a different box on the same network as the DHCP server. In fact, the Nagios box actually gets its IP address from the same DHCP server that I would like to monitor (ISC DHCP server 3.0.6 on a SuSE 10.3). I've seen the same problem before against a Windows DHCP server, too, never been able to make check_dhcp work. check_dhcp -v prints this: DHCP socket: 3 Hardware address: 00:0c:29:0e:28:4f DHCPDISCOVER to 255.255.255.255 port 67 DHCPDISCOVER XID: 2138668641 (0x7F797E61) DHCDISCOVER ciaddr: 0.0.0.0 DHCDISCOVER yiaddr: 0.0.0.0 DHCDISCOVER siaddr: 0.0.0.0 DHCDISCOVER giaddr: 0.0.0.0 send_dhcp_packet result: 548 No (more) data received (nfound: 0) Result=ERROR Total responses seen on the wire: 0 Valid responses for this machine: 0 CRITICAL: No DHCPOFFERs were received. -- Kevin Keane Owner The NetTech Find the Uncommon: Expert Solutions for a Network You Never Have to Think About Office: 866-642-7116 http://www.4nettech.com This e-mail and attachments, if any, may contain confidential and/or proprietary information. Please be advised that the unauthorized use or disclosure of the information is strictly prohibited. The information herein is intended only for use by the intended recipient(s) named above. If you have received this transmission in error, please notify the sender immediately and permanently delete the e-mail and any copies, printouts or attachments thereof. -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
I'm sorry, I already understood. But well, I did it like you told me, and I got the same outcome Running the check_dhcp on the nagios server. - Mensaje original De: jmose...@corp.xanadoo.com jmose...@corp.xanadoo.com Para: Christian Iñiguez challenger_jos...@yahoo.com.mx CC: nagios-users@lists.sourceforge.net Enviado: jueves, 15 de enero, 2009 13:25:24 Asunto: Re: [Nagios-users] check_dhcp seems not working James Moseley Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: In deed both servers (the dhcp server and nagios server) are in the same subnet and there is no firewall between them. From the nagios server I run check_nrpe!check_dhcp And in the side of dhcp server I run the command: check_dhcp -s ip_dhcp_server -t 30 Actually I'm running other services like check_load, check_procs, etc. With no problems. Just check_dhcp is not working My dhcp server is a RHEL 5 with dhcp-3.0.5-3.el5 In my previous reply, I told you that what you are trying to do above will *not* work. Do not try and check your DHCP server from the Nagios server using check_nrpe and running check_dhcp on the DHCP server itself. Run check_dhcp directly from the Nagios server. James __ Correo Yahoo! Espacio para todos tus mensajes, antivirus y antispam ¡gratis! Regístrate ya - http://correo.yahoo.com.mx/ -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
Exactly Kevin, you are right - Mensaje original De: Kevin Keane subscript...@kkeane.com CC: nagios-users@lists.sourceforge.net Enviado: jueves, 15 de enero, 2009 13:39:47 Asunto: Re: [Nagios-users] check_dhcp seems not working jmose...@corp.xanadoo.com wrote: Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: Hi Everyone I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. The command line is: check_dhcp -s serverip -t 30 What am I doing wrong? Any suggest? Thanks in advance! I have no idea which flavor of DHCP you are running (probably ISC's), but I don't think you are going to be able to run check_dhcp from the DHCP server itself. The DHCP server will see an incoming requeset from itself and probably block it. Therefore, using the nrpe method of doing these checks is a moot point. If your Nagios server is on the same network as the DHCP server, just run check_dhcp from the Nagios box. If you're running Nagios on a different network than the DHCP server and there is a firewall in between, you'll probably have to do several things: 1. Open up a hole in the firewall to allow the Nagios server to request a DHCP address from the DHCP server 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to 3. Setup a small DHCP subnet on the DHCP server in the same IP range as the Nagios server so it can offer a valid IP address I actually have the same problem as Christian, and it does NOT work even though Nagios is running on a different box on the same network as the DHCP server. In fact, the Nagios box actually gets its IP address from the same DHCP server that I would like to monitor (ISC DHCP server 3.0.6 on a SuSE 10.3). I've seen the same problem before against a Windows DHCP server, too, never been able to make check_dhcp work. check_dhcp -v prints this: DHCP socket: 3 Hardware address: 00:0c:29:0e:28:4f DHCPDISCOVER to 255.255.255.255 port 67 DHCPDISCOVER XID: 2138668641 (0x7F797E61) DHCDISCOVER ciaddr: 0.0.0.0 DHCDISCOVER yiaddr: 0.0.0.0 DHCDISCOVER siaddr: 0.0.0.0 DHCDISCOVER giaddr: 0.0.0.0 send_dhcp_packet result: 548 No (more) data received (nfound: 0) Result=ERROR Total responses seen on the wire: 0 Valid responses for this machine: 0 CRITICAL: No DHCPOFFERs were received. -- Kevin Keane Owner The NetTech Find the Uncommon: Expert Solutions for a Network You Never Have to Think About Office: 866-642-7116 http://www.4nettech.com This e-mail and attachments, if any, may contain confidential and/or proprietary information. Please be advised that the unauthorized use or disclosure of the information is strictly prohibited. The information herein is intended only for use by the intended recipient(s) named above. If you have received this transmission in error, please notify the sender immediately and permanently delete the e-mail and any copies, printouts or attachments thereof. -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null __ Correo Yahoo! Espacio para todos tus mensajes, antivirus y antispam ¡gratis! Regístrate ya - http://correo.yahoo.com.mx/ -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
Christian Iñiguez challenger_josep h...@yahoo.com.mxTo Morris, Patrick 01/15/2009 01:24 patrick.mor...@hp.com, PMnagios-users@lists.sourceforge.net cc Subject Re: [Nagios-users] check_dhcp seems not working Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: Thanks but actually the plugin is setuid root, and as user root and user nagios the outcome is the same =( Christian, Patrick is correct, and something I forgot about. The check_dhcp plugin needs to be setuid, which you've indicated it is. Can you try running check_dhcp directly from the Nagios server though? With your setup, it doesn't make sense to use check_nrpe when you can query the DHCP server directly. And as I've said, I'm not sure you are going to be able to run check_dhcp from the DHCP server itself, unless you have multiple interfaces. Morris, Patrick patrick.mor...@hp.com wrote: This one's come up a billion times or so on the list, but the most likely cause of your problem is that the plugin needs to be setuid root. James -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
Christian, actually, your question prompted me to try it again. Turned out that it was the firewall software on my Nagios box that blocked the DHCP request. As soon as I turned it off, check_dhcp worked. I'm not yet sure which ports to open to make it work with the firewall on. So far, I tried ports 67 and 68 for both TCP and UDP, but that seems not to be enough. Christian Iñiguez wrote: Exactly Kevin, you are right - Mensaje original De: Kevin Keane subscript...@kkeane.com CC: nagios-users@lists.sourceforge.net Enviado: jueves, 15 de enero, 2009 13:39:47 Asunto: Re: [Nagios-users] check_dhcp seems not working jmose...@corp.xanadoo.com wrote: Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: Hi Everyone I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. The command line is: check_dhcp -s serverip -t 30 What am I doing wrong? Any suggest? Thanks in advance! I have no idea which flavor of DHCP you are running (probably ISC's), but I don't think you are going to be able to run check_dhcp from the DHCP server itself. The DHCP server will see an incoming requeset from itself and probably block it. Therefore, using the nrpe method of doing these checks is a moot point. If your Nagios server is on the same network as the DHCP server, just run check_dhcp from the Nagios box. If you're running Nagios on a different network than the DHCP server and there is a firewall in between, you'll probably have to do several things: 1. Open up a hole in the firewall to allow the Nagios server to request a DHCP address from the DHCP server 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to 3. Setup a small DHCP subnet on the DHCP server in the same IP range as the Nagios server so it can offer a valid IP address I actually have the same problem as Christian, and it does NOT work even though Nagios is running on a different box on the same network as the DHCP server. In fact, the Nagios box actually gets its IP address from the same DHCP server that I would like to monitor (ISC DHCP server 3.0.6 on a SuSE 10.3). I've seen the same problem before against a Windows DHCP server, too, never been able to make check_dhcp work. check_dhcp -v prints this: DHCP socket: 3 Hardware address: 00:0c:29:0e:28:4f DHCPDISCOVER to 255.255.255.255 port 67 DHCPDISCOVER XID: 2138668641 (0x7F797E61) DHCDISCOVER ciaddr: 0.0.0.0 DHCDISCOVER yiaddr: 0.0.0.0 DHCDISCOVER siaddr: 0.0.0.0 DHCDISCOVER giaddr: 0.0.0.0 send_dhcp_packet result: 548 No (more) data received (nfound: 0) Result=ERROR Total responses seen on the wire: 0 Valid responses for this machine: 0 CRITICAL: No DHCPOFFERs were received. -- Kevin Keane Owner The NetTech Find the Uncommon: Expert Solutions for a Network You Never Have to Think About Office: 866-642-7116 http://www.4nettech.com This e-mail and attachments, if any, may contain confidential and/or proprietary information. Please be advised that the unauthorized use or disclosure of the information is strictly prohibited. The information herein is intended only for use by the intended recipient(s) named above. If you have received this transmission in error, please notify the sender immediately and permanently delete the e-mail and any copies, printouts or attachments thereof. -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
Sorry for the top post 1. Lease Request - The client sends a broadcast requesting an IP address 2. Lease Offer - The server sends the above information and marks the offered address as unavailable. The message sent is a DHCPOFFER broadcast message. 3. Lease Acceptance - The first offer received by the client is accepted. The acceptance is sent from the client as a broadcast (DHCPREQUEST message) including the IP address of the DNS server that sent the accepted offer. Other DHCP servers retract their offers and mark the offered address as available and the accepted address as unavailable. 4. Server lease acknowledgement - The server sends a DHCPACK or a DHCPNACK if an unavailable address was requested. All DHCP packets travel as UDP datagrams; all client-sent packets have source port 68 and destination port 67; all server-sent packets have source port 67 and destination port 68. For example, a server-side firewall should allow the following types of packets: * Incoming packets from 0.0.0.0 or dhcp-pool to dhcp-ip * Incoming packets from any address to 255.255.255.255 * Outgoing packets from dhcp-ip to dhcp-pool or 255.255.255.255 where dhcp-ip represents any address configured on a DHCP server host and dhcp-pool stands for the pool from which a DHCP server assigns addresses to clients Jim Kevin Keane wrote: Christian, actually, your question prompted me to try it again. Turned out that it was the firewall software on my Nagios box that blocked the DHCP request. As soon as I turned it off, check_dhcp worked. I'm not yet sure which ports to open to make it work with the firewall on. So far, I tried ports 67 and 68 for both TCP and UDP, but that seems not to be enough. Christian Iñiguez wrote: Exactly Kevin, you are right - Mensaje original De: Kevin Keane subscript...@kkeane.com CC: nagios-users@lists.sourceforge.net Enviado: jueves, 15 de enero, 2009 13:39:47 Asunto: Re: [Nagios-users] check_dhcp seems not working jmose...@corp.xanadoo.com wrote: Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: Hi Everyone I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. The command line is: check_dhcp -s serverip -t 30 What am I doing wrong? Any suggest? Thanks in advance! I have no idea which flavor of DHCP you are running (probably ISC's), but I don't think you are going to be able to run check_dhcp from the DHCP server itself. The DHCP server will see an incoming requeset from itself and probably block it. Therefore, using the nrpe method of doing these checks is a moot point. If your Nagios server is on the same network as the DHCP server, just run check_dhcp from the Nagios box. If you're running Nagios on a different network than the DHCP server and there is a firewall in between, you'll probably have to do several things: 1. Open up a hole in the firewall to allow the Nagios server to request a DHCP address from the DHCP server 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to 3. Setup a small DHCP subnet on the DHCP server in the same IP range as the Nagios server so it can offer a valid IP address I actually have the same problem as Christian, and it does NOT work even though Nagios is running on a different box on the same network as the DHCP server. In fact, the Nagios box actually gets its IP address from the same DHCP server that I would like to monitor (ISC DHCP server 3.0.6 on a SuSE 10.3). I've seen the same problem before against a Windows DHCP server, too, never been able to make check_dhcp work. check_dhcp -v prints this: DHCP socket: 3 Hardware address: 00:0c:29:0e:28:4f DHCPDISCOVER to 255.255.255.255 port 67 DHCPDISCOVER XID: 2138668641 (0x7F797E61) DHCDISCOVER ciaddr: 0.0.0.0 DHCDISCOVER yiaddr: 0.0.0.0 DHCDISCOVER siaddr: 0.0.0.0 DHCDISCOVER giaddr: 0.0.0.0 send_dhcp_packet result: 548 No (more) data received (nfound: 0) Result=ERROR Total responses seen on the wire: 0 Valid responses for this machine: 0 CRITICAL: No DHCPOFFERs were received. -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without
Re: [Nagios-users] check_dhcp seems not working
Kevin Keane subscript...@kkeane.com wrote: Christian, actually, your question prompted me to try it again. Turned out that it was the firewall software on my Nagios box that blocked the DHCP request. As soon as I turned it off, check_dhcp worked. I'm not yet sure which ports to open to make it work with the firewall on. So far, I tried ports 67 and 68 for both TCP and UDP, but that seems not to be enough. Kevin, that's a really good point. Christian, do you have iptables running on either the nagios or DHCP server boxes? James -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
JFTR: * jmose...@corp.xanadoo.com [2009-01-15 13:06]: If you're running Nagios on a different network than the DHCP server and there is a firewall in between, you'll probably have to do several things: 1. Open up a hole in the firewall to allow the Nagios server to request a DHCP address from the DHCP server 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to 3. Setup a small DHCP subnet on the DHCP server in the same IP range as the Nagios server so it can offer a valid IP address For such a setup, step (2) isn't necessary, as check_dhcp will mimic a DHCP relay if the --unicast option is specified. Holger -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
* Christian Iñiguez challenger_jos...@yahoo.com.mx [2009-01-15 10:46]: I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. Do you see the request and a reply in the DHCP server's logs? If so, could you verify that the server's reply reaches the host running check_dhcp using tcpdump(8) (e.g., tcpdump -vv port bootps)? Holger -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
Holger Weiss hol...@cis.fu-berlin.de wrote: * jmose...@corp.xanadoo.com [2009-01-15 13:06]: 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to For such a setup, step (2) isn't necessary, as check_dhcp will mimic a DHCP relay if the --unicast option is specified. What I meant was you'd have to have an ip helper-address configured. James -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
* jmose...@corp.xanadoo.com [2009-01-15 14:59]: Holger Weiss hol...@cis.fu-berlin.de wrote: * jmose...@corp.xanadoo.com [2009-01-15 13:06]: 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to For such a setup, step (2) isn't necessary, as check_dhcp will mimic a DHCP relay if the --unicast option is specified. What I meant was you'd have to have an ip helper-address configured. But that's precisely what you don't need if you use check_dhcp's --unicast option :-) If you configure an ip helper-address (as Cisco calls it), the router will relay local DHCP broadcast packets to the specified remote DHCP server. check_dhcp --unicast creates the same sort of unicast packets such a relay would generate. Holger -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
Holger Weiss hol...@cis.fu-berlin.de wrote: * jmose...@corp.xanadoo.com [2009-01-15 14:59]: Holger Weiss hol...@cis.fu-berlin.de wrote: * jmose...@corp.xanadoo.com [2009-01-15 13:06]: 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to For such a setup, step (2) isn't necessary, as check_dhcp will mimic a DHCP relay if the --unicast option is specified. What I meant was you'd have to have an ip helper-address configured. But that's precisely what you don't need if you use check_dhcp's --unicast option :-) If you configure an ip helper-address (as Cisco calls it), the router will relay local DHCP broadcast packets to the specified remote DHCP server. check_dhcp --unicast creates the same sort of unicast packets such a relay would generate. OK, I've got you now. Back to the orginal topic. Christian, another thing to check on the Nagios server is if you have SELinux enabled. That could definitely cause problems with plugins that are SUID root. If SELinux is enabled, disable it and try the check_dhcp plugin again. James -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
Re: [Nagios-users] check_dhcp seems not working
Thank you! In my case, the server-side firewall works without a problem. The server does hand out DHCP addresses all the time. It was the client-side firewall (i.e., the one on the Nagios server) that blocked the DHCP request, even though I opened both ports 67 and 68 for both TCP and UDP. It happened both with broadcast DHCP requests and with directed ones (using the -s serverip arg). Oddly enough, I didn't see anything at all in the firewall log that would indicate what was blocked. James Miller wrote: Sorry for the top post 1. Lease Request - The client sends a broadcast requesting an IP address 2. Lease Offer - The server sends the above information and marks the offered address as unavailable. The message sent is a DHCPOFFER broadcast message. 3. Lease Acceptance - The first offer received by the client is accepted. The acceptance is sent from the client as a broadcast (DHCPREQUEST message) including the IP address of the DNS server that sent the accepted offer. Other DHCP servers retract their offers and mark the offered address as available and the accepted address as unavailable. 4. Server lease acknowledgement - The server sends a DHCPACK or a DHCPNACK if an unavailable address was requested. All DHCP packets travel as UDP datagrams; all client-sent packets have source port 68 and destination port 67; all server-sent packets have source port 67 and destination port 68. For example, a server-side firewall should allow the following types of packets: * Incoming packets from 0.0.0.0 or dhcp-pool to dhcp-ip * Incoming packets from any address to 255.255.255.255 * Outgoing packets from dhcp-ip to dhcp-pool or 255.255.255.255 where dhcp-ip represents any address configured on a DHCP server host and dhcp-pool stands for the pool from which a DHCP server assigns addresses to clients Jim Kevin Keane wrote: Christian, actually, your question prompted me to try it again. Turned out that it was the firewall software on my Nagios box that blocked the DHCP request. As soon as I turned it off, check_dhcp worked. I'm not yet sure which ports to open to make it work with the firewall on. So far, I tried ports 67 and 68 for both TCP and UDP, but that seems not to be enough. Christian Iñiguez wrote: Exactly Kevin, you are right - Mensaje original De: Kevin Keane subscript...@kkeane.com CC: nagios-users@lists.sourceforge.net Enviado: jueves, 15 de enero, 2009 13:39:47 Asunto: Re: [Nagios-users] check_dhcp seems not working jmose...@corp.xanadoo.com wrote: Christian Iñiguez challenger_jos...@yahoo.com.mx wrote: Hi Everyone I have a linux server as dhcp server and it's working very well, and I'd like to monitoring it with nrpe plugin and check_dhcp. The problem here is the outcome of check_dhcp is always: CRITICAL: No DHCPOFFERs were received. But the server is working alright. The command line is: check_dhcp -s serverip -t 30 What am I doing wrong? Any suggest? Thanks in advance! I have no idea which flavor of DHCP you are running (probably ISC's), but I don't think you are going to be able to run check_dhcp from the DHCP server itself. The DHCP server will see an incoming requeset from itself and probably block it. Therefore, using the nrpe method of doing these checks is a moot point. If your Nagios server is on the same network as the DHCP server, just run check_dhcp from the Nagios box. If you're running Nagios on a different network than the DHCP server and there is a firewall in between, you'll probably have to do several things: 1. Open up a hole in the firewall to allow the Nagios server to request a DHCP address from the DHCP server 2. Have a DHCP relay statement on the router's interface your Nagios server connects to so it knows to which server to relay the DHCP request to 3. Setup a small DHCP subnet on the DHCP server in the same IP range as the Nagios server so it can offer a valid IP address I actually have the same problem as Christian, and it does NOT work even though Nagios is running on a different box on the same network as the DHCP server. In fact, the Nagios box actually gets its IP address from the same DHCP server that I would like to monitor (ISC DHCP server 3.0.6 on a SuSE 10.3). I've seen the same problem before against a Windows DHCP server, too, never been able to make check_dhcp work. check_dhcp -v prints this: DHCP socket: 3 Hardware address: 00:0c:29:0e:28:4f DHCPDISCOVER to 255.255.255.255 port 67 DHCPDISCOVER XID: 2138668641 (0x7F797E61) DHCDISCOVER ciaddr: 0.0.0.0 DHCDISCOVER yiaddr: 0.0.0.0 DHCDISCOVER siaddr: 0.0.0.0 DHCDISCOVER giaddr: 0.0.0.0 send_dhcp_packet result: 548 No (more) data received (nfound: 0
