| Author |
Message |
Guest
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 Posted:
Wed Oct 19, 2005 4:50 pm Post subject:
DHCP Relay and 2003 DHCP Server |
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I'm trying to consolidate my DHCP pools onto one 2003 server. Each
network is a Vlan. I setup a relay agent (called udp helper on the
3com switch) on our core. I've verified via ethereal that the server
receives the request from the relay with the correct relay agent
address, and that the DHCP server sends an ack with a valid address for
that network back to the relay agent. I've verified that the client
receives that ack via ethereal. Yet the client doesn't act like it
receives the ack and never configures itself. When I re-enable the
DHCP server that is physically in the vlan that I'm hoping to
replace, then all is well. Any input or direction would be
appreciated.
Andy |
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Phillip Windell
Guest
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Guest
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| Posted:
Thu Oct 20, 2005 8:50 pm Post subject:
Re: DHCP Relay and 2003 DHCP Server |
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Thanks for replying. The scopes were in a superscope. I removed them
from the superscope and tried it again with the same results. I
removed the scope and re-added it with the same results. |
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Phillip Windell
Guest
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Guest
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| Posted:
Fri Oct 21, 2005 7:33 am Post subject:
Re: DHCP Relay and 2003 DHCP Server |
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The superscope is gone. When I captured the traffic with ethereal,
which is shown in server.pcap linked above, I get dhcp request packets
with the correct gateway ip. Is there something else that should be
present in the request? I'll paste in the tcpdump output of the
server.pcap file showing the request and reply. The gateway is clearly
not included in that mask.
Thanks so much for you help.
13:27:07.695811 IP (tos 0x0, ttl 30, id 2003, offset 0, flags [none],
length: 328) 192.168.4.1.bootpc > 192.168.63.18.bootps: [udp sum ok]
BOOTP/DHCP, Request from 00:0e:35:68:bf:0c, length: 300, hops:1,
xid:0xaf6a8a61, secs:768, flags: [none] (0x0000)
Gateway IP: 192.168.4.1
Client Ethernet Address: 00:0e:35:68:bf:0c
Vendor-rfc1048:
DHCP:DISCOVER
NOAUTO:Y
CID:[ether]00:0e:35:68:bf:0c
RQ:192.168.5.124
HN:"orome"
VC:"MSFT 5.0"
PR:SM+DN+DG+NS+WNS+WNT+WSC+RD+SR+T249+VO
13:27:07.695906 IP (tos 0x0, ttl 128, id 14813, offset 0, flags [none],
length: 355, bad cksum 0 (->3b49)!) 192.168.63.18.bootps >
192.168.4.1.bootps: [udp sum ok] BOOTP/DHCP, Reply, length: 327,
xid:0xaf6a8a61, flags: [none] (0x0000)
Your IP: 192.168.50.14
Server IP: 192.168.63.18
Gateway IP: 192.168.4.1
Client Ethernet Address: 00:0e:35:68:bf:0c
Vendor-rfc1048:
DHCP:OFFER
SM:255.255.240.0
RN:14400
RB:25200
LT:28800
SID:192.168.63.18
DN:"academic.exeter.k12.pa.us^@"
DG:192.168.48.1
NS:192.168.63.17,192.168.63.12
WNS:192.168.63.17
WNT:h-node |
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Guest
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| Posted:
Sun Oct 23, 2005 8:50 pm Post subject:
Re: DHCP Relay and 2003 DHCP Server |
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Can someone look at this DHCP request and offer to see why the DHCP
server is handing out addresses in the wrong scope? Is the request
missing something or is it ok? Thanks in advance.
13:27:07.695811 IP (tos 0x0, ttl 30, id 2003, offset 0, flags [none],
length: 328) 192.168.4.1.bootpc > 192.168.63.18.bootps: [udp sum ok]
BOOTP/DHCP, Request from 00:0e:35:68:bf:0c, length: 300, hops:1,
xid:0xaf6a8a61, secs:768, flags: [none] (0x0000)
Gateway IP: 192.168.4.1
Client Ethernet Address: 00:0e:35:68:bf:0c
Vendor-rfc1048:
DHCP:DISCOVER
NOAUTO:Y
CID:[ether]00:0e:35:68:bf:0c
RQ:192.168.5.124
HN:"orome"
VC:"MSFT 5.0"
PR:SM+DN+DG+NS+WNS+WNT+WSC+RD+SR+T249+VO
13:27:07.695906 IP (tos 0x0, ttl 128, id 14813, offset 0, flags [none],
length: 355, bad cksum 0 (->3b49)!) 192.168.63.18.bootps >
192.168.4.1.bootps: [udp sum ok] BOOTP/DHCP, Reply, length: 327,
xid:0xaf6a8a61, flags: [none] (0x0000)
Your IP: 192.168.50.14
Server IP: 192.168.63.18
Gateway IP: 192.168.4.1
Client Ethernet Address: 00:0e:35:68:bf:0c
Vendor-rfc1048:
DHCP:OFFER
SM:255.255.240.0
RN:14400
RB:25200
LT:28800
SID:192.168.63.18
DN:"academic.exeter.k12.pa.us^@"
DG:192.168.48.1
NS:192.168.63.17,192.168.63.12
WNS:192.168.63.17
WNT:h-node |
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Phillip Windell
Guest
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| Posted:
Mon Oct 24, 2005 8:50 pm Post subject:
Re: DHCP Relay and 2003 DHCP Server |
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<AndrewZirkel@gmail.com> wrote in message
news:1130087651.387992.24180@g14g2000cwa.googlegroups.com...
| Quote: | Can someone look at this DHCP request and offer to see why the DHCP
server is handing out addresses in the wrong scope? Is the request
missing something or is it ok? Thanks in advance.
|
I don't see anything wrong with it,...but I'm not *that* big of a geek that
I chew on the contents of DHCP Queries for a snack,...so that might be
something wrong that I am not seeing. :-)
I also wouldn't know what all the IP#s go to or if they would be correct
unless I knew as much about the design of your LAN as you do.
I think you have configuration issues with the VLANs so that the replies
never get back the the Clients,...but then I would have to know as much
about your LAN's design as you do to really say for sure on that too.
--
Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com
-----------------------------------------------------
Understanding the ISA 2004 Access Rule Processing
http://www.isaserver.org/articles/ISA2004_AccessRules.html
Microsoft Internet Security & Acceleration Server: Guidance
http://www.microsoft.com/isaserver/techinfo/Guidance/2004.asp
http://www.microsoft.com/isaserver/techinfo/Guidance/2000.asp
Microsoft Internet Security & Acceleration Server: Partners
http://www.microsoft.com/isaserver/partners/default.asp
----------------------------------------------------- |
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Guest
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| Posted:
Tue Oct 25, 2005 12:50 am Post subject:
Re: DHCP Relay and 2003 DHCP Server |
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Thanks for looking at it, I really do appreciate it. Here's what I see
in that transaction (and of course I would never look at queries either
for fun).
Request:
-relayed by 192.168.4.1(ok)
-previous address of host 192.168.5.124(ok)
*This network has a mask of 255.255.252.0 so the ip is in that mask
Reply:
-to gateway 192.168.4.1 (ok)
-offered address 192.168.50.14(not in subnet)
-offered subnet 255.255.240.0(not correct)
The offered information is valid for the vlan that the server is
physically in, but not for the vlan that the client is in. This offer
does get to the client, verified by ethereal, but the client seems to
ignore it.
Is there more that needs to be in the request than the gateway address?
I'll check my vlans, but this is on a 3com core switch and there isn't
much to configure. |
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Phillip Windell
Guest
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| Posted:
Wed Oct 26, 2005 12:50 am Post subject:
Re: DHCP Relay and 2003 DHCP Server |
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<AndrewZirkel@gmail.com> wrote in message
news:1130190142.496533.176860@g47g2000cwa.googlegroups.com...
| Quote: | The offered information is valid for the vlan that the server is
physically in, but not for the vlan that the client is in. This offer
does get to the client, verified by ethereal, but the client seems to
ignore it.
|
That futher implies something wrong with the design of the VLANs of in the
way the LAN Router is configured to work with them. But again, without being
the guy who designed the VLANs I can't really say more than that. VLANs can
become a mess really fast if they are not carefully designed and
"kept-to-a-minimum",...you should preserve real physical segments (non-VLAN)
as much as possible and use VLANs to only supplement them.
--
Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com
-----------------------------------------------------
Understanding the ISA 2004 Access Rule Processing
http://www.isaserver.org/articles/ISA2004_AccessRules.html
Microsoft Internet Security & Acceleration Server: Guidance
http://www.microsoft.com/isaserver/techinfo/Guidance/2004.asp
http://www.microsoft.com/isaserver/techinfo/Guidance/2000.asp
Microsoft Internet Security & Acceleration Server: Partners
http://www.microsoft.com/isaserver/partners/default.asp
----------------------------------------------------- |
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Kevin Stephenson
Guest
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| Posted:
Sat Nov 05, 2005 7:54 am Post subject:
RE: DHCP Relay and 2003 DHCP Server |
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I am doing the exact same thing with a 3com 4924 switch using udp helper and
it is working fine. I have 7 VLAN's each with around 150 computers. There
are two DHCP servers in once VLAN and the UDP Helper settings list the two
DHCP server's IP address. I am not using superscopes but 7 individual
scopes. If you want me to list more details of my configuration I can.
Kevin
"AndrewZirkel@gmail.com" wrote:
| Quote: | I'm trying to consolidate my DHCP pools onto one 2003 server. Each
network is a Vlan. I setup a relay agent (called udp helper on the
3com switch) on our core. I've verified via ethereal that the server
receives the request from the relay with the correct relay agent
address, and that the DHCP server sends an ack with a valid address for
that network back to the relay agent. I've verified that the client
receives that ack via ethereal. Yet the client doesn't act like it
receives the ack and never configures itself. When I re-enable the
DHCP server that is physically in the vlan that I'm hoping to
replace, then all is well. Any input or direction would be
appreciated.
Andy
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Guest
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| Posted:
Mon Nov 07, 2005 5:50 pm Post subject:
Re: DHCP Relay and 2003 DHCP Server |
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Thanks for the reply. I looked over my Vlan setup and I had the port
that the dhcp server was on tagged as a member of the Vlan that was
recieving incorrect addresses. Well they were correct as the dhcp
server was seeing the initial broadcast and replying with an address in
its subnet. Once I removed that port as a tagged member then
everything worked. It was just dumb luck that I was testing the dhcp
server in that Vlan, if I had chosen another it would have worked, and
in fact that's what I did.
It's good to know that this also works with two dhcp servers. Are you
using one as a replica? If so then do you have any problems with them
handing out different addresses or keeping track of which addresses the
other hands out?
Andy
Kevin Stephenson wrote:
| Quote: | I am doing the exact same thing with a 3com 4924 switch using udp helper and
it is working fine. I have 7 VLAN's each with around 150 computers. There
are two DHCP servers in once VLAN and the UDP Helper settings list the two
DHCP server's IP address. I am not using superscopes but 7 individual
scopes. If you want me to list more details of my configuration I can.
Kevin
"AndrewZirkel@gmail.com" wrote:
I'm trying to consolidate my DHCP pools onto one 2003 server. Each
network is a Vlan. I setup a relay agent (called udp helper on the
3com switch) on our core. I've verified via ethereal that the server
receives the request from the relay with the correct relay agent
address, and that the DHCP server sends an ack with a valid address for
that network back to the relay agent. I've verified that the client
receives that ack via ethereal. Yet the client doesn't act like it
receives the ack and never configures itself. When I re-enable the
DHCP server that is physically in the vlan that I'm hoping to
replace, then all is well. Any input or direction would be
appreciated.
Andy
|
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Kevin Stephenson
Guest
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| Posted:
Wed Nov 09, 2005 1:50 am Post subject:
Re: DHCP Relay and 2003 DHCP Server |
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I have them both setup with the same scopes and one has the first half of the
addresses excluded and the other has the last half excluded. That way they
can not give out duplicate addresses but they both can give addresses out if
one is unavailable.
"AndrewZirkel@gmail.com" wrote:
| Quote: | Thanks for the reply. I looked over my Vlan setup and I had the port
that the dhcp server was on tagged as a member of the Vlan that was
recieving incorrect addresses. Well they were correct as the dhcp
server was seeing the initial broadcast and replying with an address in
its subnet. Once I removed that port as a tagged member then
everything worked. It was just dumb luck that I was testing the dhcp
server in that Vlan, if I had chosen another it would have worked, and
in fact that's what I did.
It's good to know that this also works with two dhcp servers. Are you
using one as a replica? If so then do you have any problems with them
handing out different addresses or keeping track of which addresses the
other hands out?
Andy
Kevin Stephenson wrote:
I am doing the exact same thing with a 3com 4924 switch using udp helper and
it is working fine. I have 7 VLAN's each with around 150 computers. There
are two DHCP servers in once VLAN and the UDP Helper settings list the two
DHCP server's IP address. I am not using superscopes but 7 individual
scopes. If you want me to list more details of my configuration I can.
Kevin
"AndrewZirkel@gmail.com" wrote:
I'm trying to consolidate my DHCP pools onto one 2003 server. Each
network is a Vlan. I setup a relay agent (called udp helper on the
3com switch) on our core. I've verified via ethereal that the server
receives the request from the relay with the correct relay agent
address, and that the DHCP server sends an ack with a valid address for
that network back to the relay agent. I've verified that the client
receives that ack via ethereal. Yet the client doesn't act like it
receives the ack and never configures itself. When I re-enable the
DHCP server that is physically in the vlan that I'm hoping to
replace, then all is well. Any input or direction would be
appreciated.
Andy
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