Hi all,

I am loading embedded linux kernel version 2.6.31 to our AP (Access Point) having athrose AR934x chipset. After loading the image Clients got connected to the AP. Ping between client and AP is working fine. Also the ping between client and system behind AP is working fine.Thus i am expecting that AP's bridge functionality is working fine.
The problem is when i try to ping between two connected client, it is not pinging.
I checked that arp is not able to resolve between clients (one of the client keep sending arp requests and never got the reply).Also if i manually set the arp cache on both ends then they are able to ping.

I am not able to understand where is the problem. I also find that arp request from client first reaches the AP's kernel for processing. But it was never forwarded to destination client (may be through bridge )or it is also not getting any reply from destination client.

Does i am missing some kernel configuration needs to be set.
Following is my kernel(linux-2.6.31) networking configuration while compiling:

CONFIG_PACKET=y
# CONFIG_PACKET_MMAP is not set
CONFIG_UNIX=y
CONFIG_XFRM=y
# CONFIG_XFRM_USER is not set
# CONFIG_XFRM_SUB_POLICY is not set
# CONFIG_XFRM_MIGRATE is not set
# CONFIG_XFRM_STATISTICS is not set
CONFIG_XFRM_IPCOMP=y
# CONFIG_NET_KEY is not set
CONFIG_INET=y
CONFIG_IP_MULTICAST=y
CONFIG_IP_ADVANCED_ROUTER=y
CONFIG_ASK_IP_FIB_HASH=y
# CONFIG_IP_FIB_TRIE is not set
CONFIG_IP_FIB_HASH=y
CONFIG_IP_MULTIPLE_TABLES=y
CONFIG_IP_ROUTE_MULTIPATH=y
CONFIG_IP_ROUTE_VERBOSE=y
CONFIG_IP_PNP=y
CONFIG_IP_PNP_DHCP=y
# CONFIG_IP_PNP_BOOTP is not set
CONFIG_IP_PNP_RARP=y
# CONFIG_NET_IPIP is not set
# CONFIG_NET_IPGRE is not set
CONFIG_IP_MROUTE=y
CONFIG_IP_PIMSM_V1=y
# CONFIG_IP_PIMSM_V2 is not set
CONFIG_ARPD=y
# CONFIG_SYN_COOKIES is not set
CONFIG_INET_AH=y
CONFIG_INET_ESP=y
CONFIG_INET_IPCOMP=y
CONFIG_INET_XFRM_TUNNEL=y
CONFIG_INET_TUNNEL=y
# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
# CONFIG_INET_XFRM_MODE_TUNNEL is not set
# CONFIG_INET_XFRM_MODE_BEET is not set
# CONFIG_INET_LRO is not set
# CONFIG_INET_DIAG is not set
# CONFIG_TCP_CONG_ADVANCED is not set
CONFIG_TCP_CONG_CUBIC=y
CONFIG_DEFAULT_TCP_CONG="cubic"
# CONFIG_TCP_MD5SIG is not set
CONFIG_IPV6=y
# CONFIG_IPV6_PRIVACY is not set
# CONFIG_IPV6_ROUTER_PREF is not set
# CONFIG_IPV6_OPTIMISTIC_DAD is not set
# CONFIG_INET6_AH is not set
# CONFIG_INET6_ESP is not set
# CONFIG_INET6_IPCOMP is not set
# CONFIG_IPV6_MIP6 is not set
# CONFIG_INET6_XFRM_TUNNEL is not set
# CONFIG_INET6_TUNNEL is not set
CONFIG_INET6_XFRM_MODE_TRANSPORT=y
CONFIG_INET6_XFRM_MODE_TUNNEL=y
CONFIG_INET6_XFRM_MODE_BEET=y
# CONFIG_INET6_XFRM_MODE_ROUTEOPTIMIZATION is not set
CONFIG_IPV6_SIT=y
CONFIG_IPV6_NDISC_NODETYPE=y
CONFIG_NETFILTER=y
# CONFIG_NETFILTER_DEBUG is not set
CONFIG_NETFILTER_ADVANCED=y
CONFIG_BRIDGE_NETFILTER=y
# CONFIG_BR_HOOKS_n_CASCADE_BRIDGE_ENABLED is not set
# CONFIG_BRMGMT_VAP_ENABLED is not set
# CONFIG_BRISO_ENABLED is not set
# CONFIG_HTTP_REDIRECT_ENABLED is not set
# CONFIG_MAC_ADDR_TRANSLATION is not set
# CONFIG_CONFIG_MACCLONING_ENABLED is not set

#
# Core Netfilter Configuration
#
CONFIG_NETFILTER_NETLINK=y
CONFIG_NETFILTER_NETLINK_QUEUE=y
# CONFIG_NETFILTER_NETLINK_LOG is not set
CONFIG_NF_CONNTRACK=m
CONFIG_NETFILTER_XTABLES=m
# CONFIG_NETFILTER_XT_TARGET_CLASSIFY is not set
# CONFIG_NETFILTER_XT_TARGET_CONNMARK is not set
# CONFIG_NETFILTER_XT_TARGET_DSCP is not set
# CONFIG_NETFILTER_XT_TARGET_HL is not CONFIG_NETFILTER_XT_MATCH_MAC=m
CONFIG_NETFILTER_XT_MATCH_MARK=m
# CONFIG_NETFILTER_XT_MATCH_MULTIPORT is not set
# CONFIG_NETFILTER_XT_TARGET_IMQ is not set
CONFIG_NETFILTER_XT_TARGET_MARK=m
# CONFIG_NETFILTER_XT_TARGET_NFLOG is not

#
# IP: Netfilter Configuration
#
CONFIG_NF_DEFRAG_IPV4=m
CONFIG_NF_CONNTRACK_IPV4=m
CONFIG_NF_CONNTRACK_PROC_COMPAT=y
CONFIG_IP_NF_QUEUE=m
CONFIG_IP_NF_IPTABLES=m
# CONFIG_IP_NF_MATCH_ADDRTYPE is not set
# CONFIG_IP_NF_MATCH_AH is not set
# CONFIG_IP_NF_MATCH_ECN is not set
# CONFIG_IP_NF_MATCH_TTL is not set
CONFIG_IP_NF_FILTER=m
CONFIG_IP_NF_TARGET_REJECT=m
# CONFIG_IP_NF_TARGET_LOG is not set
# CONFIG_IP_NF_TARGET_ULOG is not set
CONFIG_NF_NAT=m
CONFIG_NF_NAT_NEEDED=y
CONFIG_IP_NF_TARGET_MASQUERADE=m
# CONFIG_IP_NF_TARGET_NATTYPE is not set
# CONFIG_IP_NF_TARGET_NETMAP is not set
CONFIG_IP_NF_TARGET_REDIRECT=m
# CONFIG_NF_NAT_SNMP_BASIC is not set
# CONFIG_ATHRS_HW_NAT is not set
# CONFIG_ATHRS_HW_ACL is not set
# CONFIG_NF_NAT_FTP is not set
# CONFIG_NF_NAT_IRC is not set
# CONFIG_NF_NAT_TFTP is not set
# CONFIG_NF_NAT_AMANDA is not set
# CONFIG_NF_NAT_PPTP is not set
# CONFIG_NF_NAT_H323 is not set
# CONFIG_NF_NAT_SIP is not set
CONFIG_IP_NF_MANGLE=m
# CONFIG_IP_NF_TARGET_CLUSTERIP is not set
# CONFIG_IP_NF_TARGET_ECN is not set

CONFIG_NF_NAT=m
CONFIG_NF_NAT_NEEDED=y
CONFIG_IP_NF_TARGET_MASQUERADE=m
# CONFIG_IP_NF_TARGET_NATTYPE is not set
# CONFIG_IP_NF_TARGET_NETMAP is not set
CONFIG_IP_NF_TARGET_REDIRECT=m
# CONFIG_NF_NAT_SNMP_BASIC is not set
# CONFIG_ATHRS_HW_NAT is not set
# CONFIG_ATHRS_HW_ACL is not set
# CONFIG_NF_NAT_FTP is not set
# CONFIG_NF_NAT_IRC is not set
# CONFIG_NF_NAT_TFTP is not set
# CONFIG_NF_NAT_AMANDA is not set
# CONFIG_NF_NAT_PPTP is not set
# CONFIG_NF_NAT_H323 is not set
# CONFIG_NF_NAT_SIP is not set
CONFIG_IP_NF_MANGLE=m
# CONFIG_IP_NF_TARGET_CLUSTERIP is not set
# CONFIG_IP_NF_TARGET_ECN is not set
# CONFIG_IP_NF_TARGET_TTL is not set
# CONFIG_IP_NF_RAW is not set
# CONFIG_IP_NF_ARPTABLES is not set
# CONFIG_NF_NAT_RTSP is not set
# CONFIG_NF_CONNTRACK_RTSP is not set

#
# IPv6: Netfilter Configuration
#
# CONFIG_NF_CONNTRACK_IPV6 is not set
# CONFIG_IP6_NF_QUEUE is not set
# CONFIG_IP6_NF_IPTABLES is not set
# CONFIG_BRIDGE_NF_EBTABLES is not set
# CONFIG_IP_DCCP is not set
# CONFIG_IP_SCTP is not set
# CONFIG_TIPC is not set
# CONFIG_ATM is not set
CONFIG_STP=y
CONFIG_BRIDGE=y
CONFIG_BRIDGE_IGMP_SNOOPING=y
# CONFIG_NET_DSA is not set
CONFIG_VLAN_8021Q=y
# CONFIG_VLAN_8021Q_GVRP is not set
# CONFIG_DECNET is not set
CONFIG_LLC=y
# CONFIG_LLC2 is not set
# CONFIG_IPX is not set
# CONFIG_ATALK is not set
# CONFIG_X25 is not set
# CONFIG_LAPB is not set
# CONFIG_ECONET is not set
# CONFIG_WAN_ROUTER is not set
# CONFIG_PHONET is not set
# CONFIG_IEEE802154 is not set
CONFIG_NET_SCHED=y

Please assume some missing configurations from this list are not set.Also suggest if some extra configuration is needed.
Can also anyone explain what happens or what is the role of Access Point which sits between Clients when they wanted to ping as arp can be resolve without AP also.(like how packet transfer through kernel,etc.. or any insight).

I desperately wants an advice from some one which having experience of working on embedded linux kernels or on Access Points.

Any suggestion is heartly appreciated.
Thanks to all for your help.