Bug 524298 - dhcp client fails to setup route to not-on-local-net gateway in ARP-less device
dhcp client fails to setup route to not-on-local-net gateway in ARP-less device
Product: Fedora
Classification: Fedora
Component: dhcp (Show other bugs)
All Linux
low Severity medium
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Assigned To: Jiri Popelka
Fedora Extras Quality Assurance
Depends On:
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Reported: 2009-09-18 14:44 EDT by inakypg
Modified: 2010-11-01 16:48 EDT (History)
0 users

See Also:
Fixed In Version: dhcp-4.2.0-12.fc14
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2010-11-01 16:48:13 EDT
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RHEL 7.3 requirements from Atomic Host:
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Description inakypg 2009-09-18 14:44:06 EDT
Description of problem:

When using dhclient on certain WiMAX networks, it fails to set up local and default routes properly.

The issue is a combination of:

1 - the network DHCP server reports a default route via a gateway that is not on the local network of the wimax device

2 - the wimax device has no ARP support (it being a pure P2P link)

3 - /sbin/dhclient-script uses ARPING to determine if the gateway host is reachable or not in is_router_reachable().

When invoked, dhclient-script, in is_router_reachable, determines it is in a kind of situation 1, but then, because of 2 and 3, it fails to determine that it can actually reach the router.

Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.Try to connect to a network with said route configuration
2.Connect WiMAX, run dhclient through NM or manually
3.See it fail (check "network is unreachable" message in /var/log/messages)
Actual results:

Route table not setup properly with default route

Expected results:

dhclient-script recognizes the router as reachable and sets up default route.

Additional info:

The fix could be quite simple, by doing either of:

a. replace usage of arping in is_router_reachable() by ping (this is a drop in, since the command line arguments seem to be the same) -- this might not really work, so a variation is:

b. in is_router_reachable(), setup the 

        ip route add ${router}/32 dev ${interface}
        # error handling
        if ping -f -q -I ${interface} -w2 ${router}; then
            logmessage "DHCP router ${router} is unreachable on DHCP subnet ${mysubnet} router subnet ${routersubnet}"
            ip route del ${router}/32 dev ${interface}
Comment 1 Bug Zapper 2010-04-28 06:27:58 EDT
This message is a reminder that Fedora 11 is nearing its end of life.
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Comment 2 Jiri Popelka 2010-10-07 12:17:05 EDT
Fixed in dhcp-4.2.0-11.fc14, sorry for the huge delay.

Comment 3 inakypg 2010-10-07 13:16:36 EDT
Thank you -- I won't be able to verify (can't upgrade my machine as of now), but the same fix you applied is the one I tried back in the day.
Comment 4 Fedora Update System 2010-10-13 07:10:54 EDT
dhcp-4.2.0-12.fc14 has been submitted as an update for Fedora 14.
Comment 5 Fedora Update System 2010-10-13 17:21:31 EDT
dhcp-4.2.0-12.fc14 has been pushed to the Fedora 14 testing repository.  If problems still persist, please make note of it in this bug report.
 If you want to test the update, you can install it with 
 su -c 'yum --enablerepo=updates-testing update dhcp'.  You can provide feedback for this update here: https://admin.fedoraproject.org/updates/dhcp-4.2.0-12.fc14
Comment 6 Fedora Update System 2010-11-01 16:47:46 EDT
dhcp-4.2.0-12.fc14 has been pushed to the Fedora 14 stable repository.  If problems still persist, please make note of it in this bug report.

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