[CentOS] CentOS5U2 waiting too long when ssh login to other linux servers

The waiting time is about 50s on my CentOS box now. "yum remove
openssh* "and "yum  install openssh*" can't make it right. "mv
~/.ssh{,.bak}" not works either.
Here comes my tcpdump log, I am not an expert on SSH, Can anyone here
get me out of this?

Thanks
Ryan


[root at centos5u2 ~]# tcpdump -s 1520 -nn port 22
tcpdump: WARNING: peth0: no IPv4 address assigned
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on peth0, link-type EN10MB (Ethernet), capture size 1520 bytes
18:53:04.999533 IP 192.168.7.24.52315 > 192.168.7.252.22: S
1156562748:1156562748(0) win 5840 <mss 1460,sackOK,timestamp 5097684
0,nop,wscale 7>
18:53:04.999610 IP 192.168.7.252.22 > 192.168.7.24.52315: S
875773864:875773864(0) ack 1156562749 win 5792 <mss
1460,sackOK,timestamp 20270023 5097684,nop,wscale 7>
18:53:04.999654 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 1 win
46 <nop,nop,timestamp 5097684 20270023>
18:53:05.007974 IP 192.168.7.252.22 > 192.168.7.24.52315: P 1:21(20)
ack 1 win 46 <nop,nop,timestamp 20270032 5097684>
18:53:05.008090 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 21 win
46 <nop,nop,timestamp 5097687 20270032>
18:53:05.008344 IP 192.168.7.24.52315 > 192.168.7.252.22: P 1:21(20)
ack 21 win 46 <nop,nop,timestamp 5097688 20270032>
18:53:05.008471 IP 192.168.7.252.22 > 192.168.7.24.52315: . ack 21 win
46 <nop,nop,timestamp 20270032 5097688>
18:53:05.008715 IP 192.168.7.24.52315 > 192.168.7.252.22: P
21:733(712) ack 21 win 46 <nop,nop,timestamp 5097688 20270032>
18:53:05.009062 IP 192.168.7.252.22 > 192.168.7.24.52315: . ack 733
win 57 <nop,nop,timestamp 20270033 5097688>
18:53:05.009908 IP 192.168.7.252.22 > 192.168.7.24.52315: P
21:725(704) ack 733 win 57 <nop,nop,timestamp 20270033 5097688>
18:53:05.010074 IP 192.168.7.24.52315 > 192.168.7.252.22: P
733:757(24) ack 725 win 57 <nop,nop,timestamp 5097688 20270033>
18:53:05.012850 IP 192.168.7.252.22 > 192.168.7.24.52315: P
725:877(152) ack 757 win 57 <nop,nop,timestamp 20270036 5097688>
18:53:05.014563 IP 192.168.7.24.52315 > 192.168.7.252.22: P
757:901(144) ack 877 win 68 <nop,nop,timestamp 5097689 20270036>
18:53:05.037296 IP 192.168.7.252.22 > 192.168.7.24.52315: P
877:1597(720) ack 901 win 68 <nop,nop,timestamp 20270061 5097689>
18:53:05.039423 IP 192.168.7.24.52315 > 192.168.7.252.22: P
901:917(16) ack 1597 win 79 <nop,nop,timestamp 5097695 20270061>
18:53:05.079686 IP 192.168.7.252.22 > 192.168.7.24.52315: . ack 917
win 68 <nop,nop,timestamp 20270103 5097695>
18:53:05.079723 IP 192.168.7.24.52315 > 192.168.7.252.22: P
917:965(48) ack 1597 win 79 <nop,nop,timestamp 5097705 20270103>
18:53:05.079857 IP 192.168.7.252.22 > 192.168.7.24.52315: . ack 965
win 68 <nop,nop,timestamp 20270104 5097705>
18:53:05.079933 IP 192.168.7.252.22 > 192.168.7.24.52315: P
1597:1645(48) ack 965 win 68 <nop,nop,timestamp 20270104 5097705>
18:53:05.080312 IP 192.168.7.24.52315 > 192.168.7.252.22: P
965:1029(64) ack 1645 win 79 <nop,nop,timestamp 5097706 20270104>
18:53:05.082778 IP 192.168.7.252.22 > 192.168.7.24.52315: P
1645:1725(80) ack 1029 win 68 <nop,nop,timestamp 20270106 5097706>
18:53:05.120169 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 1725
win 79 <nop,nop,timestamp 5097716 20270106>


18:54:15.679137 IP 192.168.7.24.52315 > 192.168.7.252.22: P
1029:1173(144) ack 1725 win 79 <nop,nop,timestamp 5115354 20270106>
18:54:15.681497 IP 192.168.7.252.22 > 192.168.7.24.52315: P
1725:1757(32) ack 1173 win 79 <nop,nop,timestamp 20340699 5115354>
18:54:15.681533 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 1757
win 79 <nop,nop,timestamp 5115355 20340699>
18:54:15.681887 IP 192.168.7.24.52315 > 192.168.7.252.22: P
1173:1237(64) ack 1757 win 79 <nop,nop,timestamp 5115355 20340699>
18:54:15.685510 IP 192.168.7.252.22 > 192.168.7.24.52315: P
1757:1805(48) ack 1237 win 79 <nop,nop,timestamp 20340703 5115355>
18:54:15.685763 IP 192.168.7.24.52315 > 192.168.7.252.22: P
1237:1685(448) ack 1805 win 79 <nop,nop,timestamp 5115356 20340703>
18:54:15.701415 IP 192.168.7.252.22 > 192.168.7.24.52315: P
1805:1853(48) ack 1685 win 90 <nop,nop,timestamp 20340719 5115356>
18:54:15.701472 IP 192.168.7.252.22 > 192.168.7.24.52315: P
1853:1949(96) ack 1685 win 90 <nop,nop,timestamp 20340719 5115356>
18:54:15.701588 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 1949
win 79 <nop,nop,timestamp 5115360 20340719>
18:54:15.840022 IP 192.168.7.252.22 > 192.168.7.24.52315: P
1949:2013(64) ack 1685 win 90 <nop,nop,timestamp 20340858 5115360>
18:54:15.840076 IP 192.168.7.252.22 > 192.168.7.24.52315: P
2013:2061(48) ack 1685 win 90 <nop,nop,timestamp 20340858 5115360>
18:54:15.840188 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 2061
win 79 <nop,nop,timestamp 5115394 20340858>
18:54:15.844887 IP 192.168.7.252.22 > 192.168.7.24.52315: P
2061:2125(64) ack 1685 win 90 <nop,nop,timestamp 20340862 5115394>
18:54:15.884608 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 2125
win 79 <nop,nop,timestamp 5115406 20340862>
18:55:15.170913 IP 192.168.7.24.52315 > 192.168.7.252.22: P
1685:1733(48) ack 2125 win 79 <nop,nop,timestamp 5130226 20340862>
18:55:15.171562 IP 192.168.7.252.22 > 192.168.7.24.52315: P
2125:2173(48) ack 1733 win 90 <nop,nop,timestamp 20400184 5130226>
18:55:15.171574 IP 192.168.7.252.22 > 192.168.7.24.52315: P
2173:2237(64) ack 1733 win 90 <nop,nop,timestamp 20400184 5130226>
18:55:15.171579 IP 192.168.7.252.22 > 192.168.7.24.52315: P
2237:2301(64) ack 1733 win 90 <nop,nop,timestamp 20400184 5130226>
18:55:15.171633 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 2173
win 79 <nop,nop,timestamp 5130226 20400184>
18:55:15.171639 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 2237
win 79 <nop,nop,timestamp 5130226 20400184>
18:55:15.171644 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 2301
win 79 <nop,nop,timestamp 5130226 20400184>
18:55:17.155112 IP 192.168.7.24.52315 > 192.168.7.252.22: P
1733:1781(48) ack 2301 win 79 <nop,nop,timestamp 5130722 20400184>
18:55:17.155432 IP 192.168.7.252.22 > 192.168.7.24.52315: P
2301:2349(48) ack 1781 win 90 <nop,nop,timestamp 20402168 5130722>
18:55:17.155471 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 2349
win 79 <nop,nop,timestamp 5130722 20402168>
18:55:17.155814 IP 192.168.7.252.22 > 192.168.7.24.52315: P
2349:2413(64) ack 1781 win 90 <nop,nop,timestamp 20402168 5130722>
18:55:17.155851 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 2413
win 79 <nop,nop,timestamp 5130722 20402168>
18:55:17.155860 IP 192.168.7.252.22 > 192.168.7.24.52315: P
2413:2477(64) ack 1781 win 90 <nop,nop,timestamp 20402168 5130722>
18:55:17.155891 IP 192.168.7.24.52315 > 192.168.7.252.22: . ack 2477
win 79 <nop,nop,timestamp 5130722 20402168>

50 packets captured
100 packets received by filter
0 packets dropped by kernel
[root at centos5u2 ~]#
[root at centos5u2 ~]#



-- 
FIXME if it is wrong.