unable to do snmpwalk from monitoring server to snmp client

I have ServerA and ServerB, ServerA is monitoring server and ServerB is SNMP client. SNMPWALK from serverA to serverB is getting timeout error, please help me to resolve this issue. I am able to do snmpwalk from serverA to other servers so there is no problem with ServerA. network port opened 161, 162 and 199 opened on routers in bidirectional way between source ip and destination ip so there is no issue with network as well. some configuration issue with ServerB, community string is same between two servers.

ServerA's config

cat /etc/issue
CentOS release 5.5 (Final)
Kernel \r on an \m


snmpd -v
NET-SNMP version:
Web:               http://www.net-snmp.org/
Email:             net-snmp-coders@lists.sourceforge.net

netstat -plan | grep snmp
tcp        0      0     *                   LISTEN      3807/snmpd
udp        0      0     *                               22860/snmpwalk
udp        0      0     *                               22944/snmpwalk
udp        0      0       *                               3807/snmpd
udp        0      0     *                               22909/snmpwalk
udp        0      0     *                               22953/snmpwalk
udp        0      0     *                               22918/snmpwalk
udp        0      0     *                               22861/snmpwalk
udp        0      0     *                               22870/snmpwalk
udp        0      0     *                               22946/snmpwalk
unix  2      [ ]         DGRAM                    8710   3807/snmpd

nc -zu ServerB 161
Connection to ServerB port [udp/snmp] succeeded!

snmpwalk -v2c -cstring ServerB
Timeout: No Response from ServerB

ServerB's Config

cat /etc/issue
CentOS release 6.4 (Final)
Kernel \r on an \m

 snmpd -v

NET-SNMP version:  5.5
Web:               http://www.net-snmp.org/
Email:             net-snmp-coders@lists.sourceforge.net

rpm -qa | grep snmp

netstat -plan | grep snmp
tcp        0      0     *                   LISTEN      7978/snmpd
udp        0      0       *                               7978/snmpd
unix  2      [ ]         DGRAM                    1378957 7978/snmpd

nc -zu ServerA 161
Connection to ServerA 161 port [udp/snmp] succeeded!
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Have you verify the version of snmp is configured as v2 on the client? Is this the only Centos 6 client you are having issue?
sudhirgoogleAuthor Commented:
how do i check that ?
Can you post snmp.conf?

Try -

snmpwalk -v1 -cstring ServerB

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sudhirgoogleAuthor Commented:
On ServerB

cat /etc/snmp/snmpd.conf
rocommunity string

On ServerA
snmpwalk -v1 -cstring ServerB
Timeout: No Response from ServerB

FYI. I am able to do snmpwalk from ServerB to ServerA.
Do you have snmpd running on target and 161 udp allowed in system-config-firewall-tui ?
Can you run snmp query locally on that machine?

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sudhirgoogleAuthor Commented:
Thanks for all your support guys. Issue resolved. This issue is due to firewall, on firewall after enabling bidirectional access to 161 & 162 UDP port from monitoring server to snmp client host then it started working.
sudhirgoogleAuthor Commented:
I've requested that this question be closed as follows:

Accepted answer: 0 points for sudhirgoogle's comment #a40014545

for the following reason:

thanks for the support
i mentioned firewall, ok you may have come to parallel discovery of same.
Usually for thanks you give b grades or c grades instead of pulling out with nothing.
Should be grade  A to Gheist. Gheist mentioned firewall again regardless asker claimed to have checked firewall on the first post.
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