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[bug #53754] RFC violation: grub2 uses bootp-gateway IP as router
From: |
Alexandra Faust |
Subject: |
[bug #53754] RFC violation: grub2 uses bootp-gateway IP as router |
Date: |
Wed, 25 Apr 2018 14:22:59 -0400 (EDT) |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:59.0) Gecko/20100101 Firefox/59.0 |
URL:
<http://savannah.gnu.org/bugs/?53754>
Summary: RFC violation: grub2 uses bootp-gateway IP as router
Project: GNU GRUB
Submitted by: medic123de
Submitted on: Wed 25 Apr 2018 06:22:58 PM UTC
Category: Network
Severity: Major
Priority: 5 - Normal
Item Group: None
Status: None
Privacy: Public
Assigned to: None
Originator Name:
Originator Email:
Open/Closed: Open
Discussion Lock: Any
Release:
Release: Git master
Reproducibility: Every Time
Planned Release: None
_______________________________________________________
Details:
Hi Guys,
sadly I ran into an issue today.
we have several networks and use Ciscos IOS DHCP-helper to reflect dhcp/bootp
requests to our DHCP/BootP server.
Cisco sets the giaddr field to itself, but does not forward regular traffic (
as currently in standby ).
now grub2 kicks in and sets a hostroute to the bootp-server via that router.
sadly, that server is supposed to serve bootfiles also via tftp - and now does
timeout.
RFC 1542 states:
A BOOTP client MUST NOT interpret the 'giaddr' field of a BOOTREPLY
message to be the IP address of an IP router. A BOOTP client SHOULD
completely ignore the contents of the 'giaddr' field in BOOTREPLY
messages.
DISCUSSION:
The semantics of the 'giaddr' field were poorly defined.
Section 7.5 of [1] states:
"If 'giaddr' (gateway address) is nonzero, then the packets
should be forwarded there first, in order to get to the
server."
In that sentence, "get to" refers to communication from the client to
the server subsequent to the BOOTP exchange, such as a TFTP session.
Unfortunately, the 'giaddr' field may contain the address of a BOOTP
relay agent that is not itself an IP router (according to [1],
Section 8, fifth paragraph), in which case, it will be useless as a
first-hop for TFTP packets sent to the server (since, by definition,
non-routers don't forward datagrams at the IP layer).
https://tools.ietf.org/html/rfc1542#section-3.4
can you please repair it in any way ?
( i tried to overwrite with DHCP static routes - but that didn't work either
)
nests
Alex
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Wed 25 Apr 2018 06:22:58 PM UTC Name: efi-route.jpg Size: 25KiB By:
medic123de
<http://savannah.gnu.org/bugs/download.php?file_id=44032>
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- [bug #53754] RFC violation: grub2 uses bootp-gateway IP as router,
Alexandra Faust <=