RHBA-2011:1038 - Bug Fix Advisory

Topic

Updated dhcp packages that fix several bugs and add an enhancement are now
available for Red Hat Enterprise Linux 5.

Description

The Dynamic Host Configuration Protocol (DHCP) is a protocol that allows
individual devices on an IP network to get their own network configuration
information, including an IP address, a subnet mask, and a broadcast address.
DHCPv6 is the DHCP protocol version for IPv6 networks.

This update fixes the following bugs:

• Previously, the dhcpd service sometimes started to give new leases to clients

in the INIT state rather than to presently active clients. That led to premature
exhaustion of available leases for new clients. With this update, the server's
"by client-id" and "by hardware address" hash table lists are sorted according
to the preference to re-allocate the lease to returning clients, and the pool
starvation problem no longer occurs in the described scenario. (BZ#615995)

• Previously, moving the server from the "communication-interrupted" state to

the "partner-down" state did not force the server to take over the partner's
leases. Consequently, clients could not get an IP address from the pool of the
previously terminated DHCP server. With this update, a failover server in
"partner-down" state is able to re-allocate leases to clients. (BZ#610219)

• Previously, the dhclient utility wasn't requesting the interface-mtu option by

default. This caused difficulties when the network configuration changed and the
MTU (Maximum Transmission Unit) value needed to be changed on all hosts. With
this update, the dhclient utility requests the interface-mtu option by default.
(BZ#694264)

• Previously, the dhcpd init script lacked several variables and actions

required by the Linux Standard Base (LSB). With this update, the init script has
been amended and it is now LSB-compliant. (BZ#610128)

• Previously, when the dhcpd service was used in a failover configuration, the

primary server sometimes wrote so many "lease imbalance" messages into its log
files, that it resulted in a termination. With this update, these messages are
not logged unless rebalance is attempted, and the bug no longed occurs.
(BZ#661939)

• Previously, when the system had been rebooted while the network switch had

been down, after the network connection was recovered, the network interface
configuration was not configured with DHCP, even if the dhclient utility was
running in persistent mode. With this update, the dhclient-script file has been
amended to refresh the ARP (Address Resolution Protocol) table and the routing
table instead of bringing the interface down, which fixes the bug. (BZ#685048)

• Previously, when multiple DHCP clients were launched at the same time to

handle multiple virtual interfaces on the same network interface card (NIC), the
clients used the same seed to choose when to renew their leases. Consequently,
virtual interfaces for some clients could have been deconfigured over time. With
this update, the dhclient utility uses the PID (Process Identifier) for seeding
the random number generator, which fixes the bug. (BZ#623953)

• Previously, it was impossible to configure the dhcrelay service to run the

dhcrelay daemon with additional arguments. With this update, a DHCRELAYARGS
variable is available for the /etc/sysconfig/dhcrelay configuration file, which
allows additional arguments to be passed to the dhcrelay daemon properly.
(BZ#624965)

• There was a small error regarding the dhcp-lease-time option in the

dhclient.conf(5) man page. With this update, the man page has been amended.
(BZ#585855)

This update adds the following enhancement:

• The dhcp package now provides support for IPoIB (IP over InfiniBand)

interfaces. (BZ#660679)

Users of dhcp are advised to upgrade to these updated packages, which fix these
bugs and add this enhancement.

Solution

Before applying this update, make sure that all previously-released errata
relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use the Red
Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 585855 - error in man page of dhclient.conf
• BZ - 610128 - Make dhcpd init script LSB compliant
• BZ - 610219 - When dhcp server is moved after failover into partner-down state, it doesn't take over partner's leases after MCLT expiration
• BZ - 615995 - dhcpd offers multiple ip addresses to the same mac address
• BZ - 623953 - Multiple dhclients can steal each others' DHCPOFFERs
• BZ - 624965 - Can't add extra arguments to dhcrelay daemon
• BZ - 660679 - (Mellanox5.7) Add IPoIB support in DHCP
• BZ - 661939 - dhcp primary server keeps outputing "lease imbalance" messages
• BZ - 685048 - No IP connectivity with DHCP when Link was down on boot

CVEs

(none)

References

(none)