1

I have 3650 Switch which contain number of VLAN and I am unable to connect to one ip address from specific VLAN. But routing is properly configured and there is no ACL applied. Even end device has no any additional configurations. End device is a server and even firewall also switched off.

I am unable to Login to 192.168.2.10 (VLAN Y) from VLAN X

ACL

10 deny ip 192.168.2.0 0.0.0.255 192.168.100.0 0.0.0.255
20 permit ip any any

SVI

interface VlanX
 ip address 192.168.15.253 255.255.255.0
 ip helper-address 192.168.2.13
 ip helper-address 192.168.2.12
!

interface VlanY
 ip address 192.168.2.253 255.255.255.0

Routing

3650E#sh running-config | s ip ro
ip routing
ip route 0.0.0.0 0.0.0.0 192.168.2.1
ip route 172.25.20.0 255.255.255.0 192.168.2.9
ip route 192.168.1.0 255.255.255.0 192.168.2.9
ip route 192.168.2.0 255.255.255.0 Vlan130
alias exec sir show ip route

Interface VLANX

3650#sh interfaces vlan 170
Vlan170 is up, line protocol is up
  Hardware is Ethernet SVI, address is 707d.b99f.9dc0 (bia 707d.b99f.9dc0)

  Internet address is 192.168.15.253/24
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 289000 bits/sec, 74 packets/sec
  5 minute output rate 844000 bits/sec, 84 packets/sec
     19196205 packets input, 3953954717 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     27249461 packets output, 34700295919 bytes, 0 underruns
     0 output errors, 2 interface resets
     0 unknown protocol drops
     0 output buffer failures, 0 output buffers swapped out

Interface VLANY

3650#sh interfaces vlan 130
Vlan130 is up, line protocol is up
  Hardware is Ethernet SVI, address is 707d.b99f.9dfe (bia 707d.b99f.9dfe)
  Internet address is 192.168.2.253/24
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 21/255, rxload 4/255
  Encapsulation ARPA, loopback not set
  Keepalive not supported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 17100000 bits/sec, 3322 packets/sec
  5 minute output rate 83756000 bits/sec, 9216 packets/sec
     478013275 packets input, 314465949967 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     1008540150 packets output, 915840064290 bytes, 0 underruns
     0 output errors, 2 interface resets
     12153 unknown protocol drops
     0 output buffer failures, 0 output buffers swapped out

I can ping all ip address except 192.168.2.10 in VLAN Y from VLAN X.

5
  • Can you ping the server from other devices in VLAN Y?
    – Ron Trunk
    Oct 25 '19 at 10:50
  • Yes. But i can ping to SVI of VLAN x from server. i cannot ping to devices in VLAN x from server
    – infra
    Oct 25 '19 at 11:28
  • 2
    This sounds exactly like a default gateway is wrong or missing. What is the default gateway on the 192.168.2.10 server?
    – Glen
    Oct 25 '19 at 12:49
  • 1
    Please include the full switch configuration. There are other configurations that could affect this, and you have not included them. It helps us to see everything.
    – Ron Maupin
    Oct 25 '19 at 13:20
  • 1
    It also sounds a a difference in subnet mask on the end point. Please provide ip configuration of the end points.
    – MatsK
    Oct 26 '19 at 22:24
1

Problem was on Server, it has changed default gateway and unfortunately it also has routing configured. Therefore communication happened for one way.

3
  • Yes, I cannot count the number of times I had to point out to server guys that either the gateway or network mask was configured incorrectly on the server. They have a very hard time if the prefix length is anything but a /24.
    – Ron Maupin
    Nov 4 '19 at 14:26
  • @RonMaupin Problem is system administrator is separate person and therefore she said no problem with server end. I have no access to server...
    – infra
    Nov 5 '19 at 3:30
  • Yes, I have the same problem. It just gets worse when the server guys have someone like IBM install the server, and they swear that the server is completely correct, but it is the fault of the network configuration. It is often like pulling teeth to get what the server was configured as, and it is almost always a server configuration problem because the servers are always configured with a /24, regardless of the network configuration.
    – Ron Maupin
    Nov 5 '19 at 4:34

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