Cisco 3750x blocking ports?
Hey experts. I am working through an issue that is affecting my Sophos updates and Websense filtering. Each service is on a different server but located on the same network. We recently put a Cisco 3750x into production which replaced a Nortel 325-24G. All of our network traffic comes to this switch before going out to a Contivity 1730 which is managed by a state agency. I've worn out the state support and they show that the firewall at our location should be able to allow ports 8192 and 8194. I haven't done much with the 3750x so I'm not sure if that switch is in play with the inability of the Sophos server to get updates or the Websense filtering to function properly. Both of the issues relating to Sophos and Websense occurred when we put the new Cisco switch in place.
How do I test whether the Cisco switch is or isn't blocking traffic on those ports (if that is even possible)?
Thank you in advance for your help and time.
How do I test whether the Cisco switch is or isn't blocking traffic on those ports (if that is even possible)?
Thank you in advance for your help and time.
ASKER
Hi Akinsd. Thanks for replying. I never got notification that an expert had responded so I apologize for the delay. I ran the commands as you stated and here are the results.
Core_40#show ip access-list
Extended IP access list preauth_ipv4_acl (per-user)
10 permit udp any any eq domain
20 permit tcp any any eq domain
30 permit udp any eq bootps any
40 permit udp any any eq bootpc
50 permit udp any eq bootpc any
60 deny ip any any
Core_40#show access-list
Extended IP access list preauth_ipv4_acl (per-user)
10 permit udp any any eq domain
20 permit tcp any any eq domain
30 permit udp any eq bootps any
40 permit udp any any eq bootpc
50 permit udp any eq bootpc any
60 deny ip any any
IPv6 access list preauth_ipv6_acl (per-user)
permit udp any any eq domain sequence 10
permit tcp any any eq domain sequence 20
permit icmp any any nd-ns sequence 30
permit icmp any any nd-na sequence 40
permit icmp any any router-solicitation sequence 50
permit icmp any any router-advertisement sequence 60
permit icmp any any redirect sequence 70
permit udp any eq 547 any eq 546 sequence 80
permit udp any eq 546 any eq 547 sequence 90
deny ipv6 any any sequence 100
I can't decipher what this means. Does this mean ports 8192 and 8194 are allowed?
Core_40#show ip access-list
Extended IP access list preauth_ipv4_acl (per-user)
10 permit udp any any eq domain
20 permit tcp any any eq domain
30 permit udp any eq bootps any
40 permit udp any any eq bootpc
50 permit udp any eq bootpc any
60 deny ip any any
Core_40#show access-list
Extended IP access list preauth_ipv4_acl (per-user)
10 permit udp any any eq domain
20 permit tcp any any eq domain
30 permit udp any eq bootps any
40 permit udp any any eq bootpc
50 permit udp any eq bootpc any
60 deny ip any any
IPv6 access list preauth_ipv6_acl (per-user)
permit udp any any eq domain sequence 10
permit tcp any any eq domain sequence 20
permit icmp any any nd-ns sequence 30
permit icmp any any nd-na sequence 40
permit icmp any any router-solicitation sequence 50
permit icmp any any router-advertisement sequence 60
permit icmp any any redirect sequence 70
permit udp any eq 547 any eq 546 sequence 80
permit udp any eq 546 any eq 547 sequence 90
deny ipv6 any any sequence 100
I can't decipher what this means. Does this mean ports 8192 and 8194 are allowed?
Those are default Dynamic ACLs on the 3750.
Try show ip interfaces to verify that no acl is applied to any switchport
Technically, based on the configuration in the dynamic acl above, the deny list at the end means anything not permitted in the permit statements will be denied.
However, the traffic in question should not be affected by those ACL assuming default settings are in place.
Let's concentrate on the switchports the servers are connected to and the exit port to the firewall.
Do you have a lower grade switch to connect the servers to for testing?
Try show ip interfaces to verify that no acl is applied to any switchport
Technically, based on the configuration in the dynamic acl above, the deny list at the end means anything not permitted in the permit statements will be denied.
However, the traffic in question should not be affected by those ACL assuming default settings are in place.
Let's concentrate on the switchports the servers are connected to and the exit port to the firewall.
Do you have a lower grade switch to connect the servers to for testing?
ASKER
The switch that was replaced by the new Cisco switch was a Nortel 325-24G. I am working on putting that switch back in place and seeing if the problem exists.
The internal network traffic comes into the new Cisco switch and leaves on this port 21.
I ran the "show ip interfaces" command and copied the results relating to port 21
GigabitEthernet1/0/21 is up, line protocol is up
Inbound access list is not set
So does this mean that there is no ACL on port 21?
The internal network traffic comes into the new Cisco switch and leaves on this port 21.
I ran the "show ip interfaces" command and copied the results relating to port 21
GigabitEthernet1/0/21 is up, line protocol is up
Inbound access list is not set
So does this mean that there is no ACL on port 21?
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ASKER
It appears the problem may come down to packets being tagged now versus not being tagged before. We've added two VLANS when we only had one with the previous config. With the assistance of the Websense support folks, we may have it ruled out today.
I'm going to award points/grade and close out this question as I know now (from your posts) that there is no ACL on the ports in question.
Thank you for your help!!
I'm going to award points/grade and close out this question as I know now (from your posts) that there is no ACL on the ports in question.
Thank you for your help!!
You're welcome
All the best
All the best
OR
show access-list
Run either of the commands above and see what is blocked or what is allowed
I access lists exist on switchports that affect the servers, you will need to add permission for the port on those ACLs