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Bootstrap Protocol (offer) [closed]

HI all,

I can see Option 150 with unknown TFTP Servers? But in DHCP Option 150 is set to myserver.domain.com

Bootstrap

As

aussupport's avatar
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aussupport
asked 2018-08-14 06:04:30 +0000
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Closed for the following reason "duplicate question" by aussupport 2018-08-15 09:59:27 +0000

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1 Answer

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RFC5859 states that DHCP option 150 must contain IPv4 address, not domain name. Please check your DHCP server configuration.

And also check your DHCP option 66 (TFTP Server Name option) which is present in the offer.

Packet_vlad's avatar
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Packet_vlad
answered 2018-08-14 06:23:07 +0000, updated 2018-08-14 06:26:23 +0000
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I couldn't find any of these IP's?

TFTP

Not in DHCP? As

aussupport's avatar aussupport (2018-08-14 11:12:26 +0000) edit

Could you please be more specific in your question? Can't find these IP where exactly? In your network? Can't use them? In DHCP server configuration?

Keep in mind you're not communicating with DHCP server directly, DHCP relay agent is in use. Non-zero Relay agent IP address indicates it. An IP of actual DHCP server is in DHCP server identifier option 54. Spot this IP, look at actual DHCP server configuration and you'll find these IP addresses there.

Packet_vlad's avatar Packet_vlad (2018-08-14 13:06:33 +0000) edit

Hi,

You can see these IP's in that image on TFTP Link.

Option: (150) TFTP Server Address TFTP Server Address: 99.105.99.52 TFTP Server Address: 45.112.114.111 TFTP Server Address: 100.46.115.101 TFTP Server Address: 114.99.111.98 TFTP Server Address: 112.111.46.99 TFTP Server Address: 111.109.46.97 [Expert Info (Error/Protocol): Option length isn't a multiple of 4]

Option: (54) DHCP Server Identifier DHCP Server Identifier: 10.1.171.1

In DHCP Server

Option 150 is set for myserver.domain.com

As

aussupport's avatar aussupport (2018-08-15 01:04:20 +0000) edit

What you see is the IP address interpretation of the text "myserver.domain.com". If you fill in text "myserver.domain.com" the ASCII character values are interpreted as IP addresses by Wireshark, since that is the required format. I bet the real domain name you typed in started with "cic4-prod".

Jaap's avatar Jaap (2018-08-15 05:01:42 +0000) edit

Thanks for your help.

aussupport's avatar aussupport (2018-08-15 09:58:55 +0000) edit
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