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Strange Switch behavior

Hello,

 

We tried to RDP today to a server connected to port 48 of a WS-C2960L-48PS-LL, but could not.  We then moved it to port 2 on the same switch and could. At this time, we also tested a few TCP ports with a tool designed to listen on whichever port is specified and could not get it to work on port 48, but could on port 2.  Certain well known ports work on both, but certain ones do not.  An example of one that worked on both was port 445, and two examples of TCP/UDP ports that did not work while connected to port 48 was ports 5440 and 3389. 

 

Just so you know, port 2 is assigned to vlan 1 (and the IP assigned is 192.168.11.99); while port 48 is assigned to vlan 111 (IP assigned: 192.168.111.100).  The difference is that vlan 111 is configured for dhcp on the switch while vlan 1 is configured to use a dhcp on a server in the same vlan.  The server in question uses static IP addressing so it doesn’t receive a dynamically assigned address either way.  I confirmed there are no duplicate IP assignments regarding 192.168.111.100 because I cannot ping it with the device now assigned 192.168.11.99, and I was able to extract the same mac address from the arp cache for both IPs prior to the old one being flushed from the cache. 

 

While on port 48 (and with the old IP), I can ping the device, telnet to TCP ports like 445, and see error-free bidirectional traffic on the interface.  However, I just noticed that, while on port 2, I can ping 192.168.11.99 from vlan 1, but not from vlan 99.  This was not the only IP address like this.  I tried pinging two other IPs from vlan 1 with the same effect.  The reverse, however, does not seem to hold true, as I can ping devices from vlan 100, while in vlan 99.  I confirmed IP routing IS enabled on the switch.

 

Pinging devices from vlan 1 from both vlans:

 

cc-Milan-PhoneSwitch#ping 192.168.11.99 source vlan 1    

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.11.99, timeout is 2 seconds:

Packet sent with a source address of 192.168.11.11

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

cc-Milan-PhoneSwitch#ping 192.168.11.99 source vlan 111

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.11.99, timeout is 2 seconds:

Packet sent with a source address of 192.168.111.1

.....

Success rate is 0 percent (0/5)

cc-Milan-PhoneSwitch#ping 192.168.11.21 source vlan 1 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.11.21, timeout is 2 seconds:

Packet sent with a source address of 192.168.11.11

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/82/407 ms

cc-Milan-PhoneSwitch#ping 192.168.11.21 source vlan 111

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.11.21, timeout is 2 seconds:

Packet sent with a source address of 192.168.111.1

.....

Success rate is 0 percent (0/5)

cc-Milan-PhoneSwitch#ping 192.168.11.101 source vlan 1 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.11.101, timeout is 2 seconds:

Packet sent with a source address of 192.168.11.11

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

cc-Milan-PhoneSwitch#ping 192.168.11.202 source vlan 1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.11.202, timeout is 2 seconds:

Packet sent with a source address of 192.168.11.11

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/5 ms

cc-Milan-PhoneSwitch#ping 192.168.11.202 source vlan 111

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.11.202, timeout is 2 seconds:

Packet sent with a source address of 192.168.111.1

.....

Success rate is 0 percent (0/5)

cc-Milan-PhoneSwitch#ping  192.168.11.213 source vlan 1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.11.213, timeout is 2 seconds:

Packet sent with a source address of 192.168.11.11

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 2/3/8 ms

cc-Milan-PhoneSwitch#ping  192.168.11.213 source vlan 111

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.11.213, timeout is 2 seconds:

Packet sent with a source address of 192.168.111.1

.....

Success rate is 0 percent (0/5)

 

 

Pinging devices from vlan 111 from both vlans:

 

cc-Milan-PhoneSwitch#ping 192.168.111.101 source vlan 1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.111.101, timeout is 2 seconds:

Packet sent with a source address of 192.168.11.11

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

cc-Milan-PhoneSwitch#ping 192.168.111.101 source vlan 111

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.111.101, timeout is 2 seconds:

Packet sent with a source address of 192.168.111.1

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

cc-Milan-PhoneSwitch#ping 192.168.111.202 source vlan 1 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.111.202, timeout is 2 seconds:

Packet sent with a source address of 192.168.11.11

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

cc-Milan-PhoneSwitch#ping 192.168.111.202 source vlan 111

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.111.202, timeout is 2 seconds:

Packet sent with a source address of 192.168.111.1

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

cc-Milan-PhoneSwitch#ping 192.168.111.109 source vlan 1 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.111.109, timeout is 2 seconds:

Packet sent with a source address of 192.168.11.11

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/7 ms

cc-Milan-PhoneSwitch#ping 192.168.111.109 source vlan 111

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.111.109, timeout is 2 seconds:

Packet sent with a source address of 192.168.111.1

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

cc-Milan-PhoneSwitch#ping 192.168.111.214 source vlan 1 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.111.214, timeout is 2 seconds:

Packet sent with a source address of 192.168.11.11

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

cc-Milan-PhoneSwitch#ping 192.168.111.214 source vlan 111

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.111.214, timeout is 2 seconds:

Packet sent with a source address of 192.168.111.1

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

 

 

IP Routing is enabled:

 

cc-Milan-PhoneSwitch#sho run | i ip routing

ip routing

cc-Milan-PhoneSwitch#

 

 

There appears to be something appears to be going on here that I think we need to go a little further with.  Can someone please provide input with what may be going on?  Just a little extra bit of information, we have not ruled out something physical happening with it.  We just can't figure out what.

1 REPLY 1
Highlighted
VIP Advisor

Re: Strange Switch behavior

Hello


@macgyver0099_1 wrote:

While on port 48 (and with the old IP), I can ping the device, telnet to TCP ports like 445, and see error-free bidirectional traffic on the interface.  However, I just noticed that, while on port 2, I can ping 192.168.11.99 from vlan 1, but not from vlan 99.  This was not the only IP address like this.  I tried pinging two other IPs from vlan 1 with the same effect.  The reverse, however, does not seem to hold true, as I can ping devices from vlan 100, while in vlan 99.  I confirmed IP routing IS enabled on the switch


I would check for access-lists negating communication



kind regards
Paul

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