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fosiul01Flag for United Kingdom of Great Britain and Northern Ireland

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route problem

Hi

I have 2 server in 2 subnet . and I can conferm the routing in router is fine. there is not any issue and both server is same switch .

1st  : 172.21.2.2
2nd  : 172.21.0.2

gateway is : 172.21.0.1

Problem is :

when i do traceroute from 172.21.2.2 to Any server in 172.21.0.x .. it cant find the route first time .
example :


 traceroute  172.21.0.33
traceroute to 172.21.0.33 (172.21.0.33), 30 hops max, 40 byte packets
 1  172.21.0.33 (172.21.0.33)  0.381 ms * *
web-by:~# traceroute  172.21.0.33
traceroute to 172.21.0.33 (172.21.0.33), 30 hops max, 40 byte packets
 1  172.21.0.33 (172.21.0.33)  0.605 ms * *
web-by:~# traceroute  172.21.0.33
traceroute to 172.21.0.33 (172.21.0.33), 30 hops max, 40 byte packets
 1  172.21.0.33 (172.21.0.33)  0.462 ms * *
web-by:~# traceroute -I  172.21.0.33
traceroute to 172.21.0.33 (172.21.0.33), 30 hops max, 40 byte packets
 1  172.21.0.33 (172.21.0.33)  0.617 ms  0.617 ms  0.616 ms

but if i use traceroute -I. its works straightway .


now another example :
 traceroute 172.21.0.31
traceroute to 172.21.0.31 (172.21.0.31), 30 hops max, 40 byte packets
 1  172.21.0.31 (172.21.0.31)  5.159 ms  0.252 ms  0.109 ms
web-by:~# traceroute 172.21.0.31
traceroute to 172.21.0.31 (172.21.0.31), 30 hops max, 40 byte packets
 1  172.21.0.31 (172.21.0.31)  0.508 ms  0.505 ms  0.500 ms

after I press enter  , there is a pause for like 10 secons then it will find the route ..



Now : this is not a routing problem of the router .
becaue : there is a another server in same subnet
172.21.2.3
its works fine . there is not any issue with that .

so I belived the issue is in 172.21.2.2

the netstart output

Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
172.21.0.0      0.0.0.0         255.255.0.0     U         0 0          0 eth0
0.0.0.0         172.21.0.1      0.0.0.0         UG        0 0          0 eth0

even though 172.21.2.2 and 172.21.2.3 is in same subnet

if i execute this command

traceroute 172.21.2.3
traceroute to 172.21.2.3 (172.21.2.3), 30 hops max, 40 byte packets   ::::: after this line there will be long pause .. then it will go to bellow line
 1  172.21.2.3 (172.21.2.3)  3.092 ms  3.096 ms  3.102 ms


so it has problem to go to 172.21.2.3 aswell .

but ping is fine .. no issue ..

i am now little bit of puzzled what could cause the issue .

if any one can give me some hand to solve the issue. i would be greatfull ..

regards

 
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network mask must be 24 bits (255.255.255.0) : thats not the issue

by using 255.255.0.0 , you just useing loads of host that all.

its nothing to do with this problem.

if you read the question, i said, same network setting on 2 server   172.21.2.2 and 172.21.2.3  , but problem is on 172.21.2.2.
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. change netmask to 24 bits in all hosts in this subnets  : as I said, dont worry about subnet mask .
We have 2 different site. and they have different subnet  . they all works fine. So i know thats not the isseue .

example : we have another sites , where 172.31.2.2  / 255.255.0.0  , they all works fine . so again, dont worry abotu subnet . they nto the issue .


i past, netstat output on my question, but here is route

 route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
localnet        *               255.255.0.0     U     0      0        0 eth0
default         172.21.0.1      0.0.0.0         UG    0      0        0 eth0


I will add
GATEWAYDEV=<ethx>
see if that helps..


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GATEWAYDEV=<ethx>   : with this.... this server did not pickup any networkinterface

this server is in denmark. so i had to call up site engineer. to remove that line
then it came up online .. again..
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sorry. i suppose to say, dont worry abotu the mask which is : 255.255.0.0

I belived .. 172.21.2.2 and 172.21.0.2 is same subnet ..
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