Showing results for 
Search instead for 
Did you mean: 

Community Helping Community


Internet slowness

Hi All, Recently our users started reporting that their internet connectivity is extremely slow . We have a 20 Meg connection and straight away when we checked couple of things like bandwidth utilization it is well under normal but still they have slowness.

Our set up is we have a Catalyst stack switch that has a physical connection to an ISP circuit. For layer 3 we use Router and firewall for Nat when connecting to Internet. We suspected interface mismatch settings and we could see our physical connection interface is running in full duplex and 100M speed. This is the same in ISP end as well. Also our firewall outside interface is set to auto full duplex and auto 100 M speed . Also checked there is no input errors , CRC , output drops and buffers. Still our users are facing extreme slowness. Any inputs is much appreciated.

VIP Advisor

Re: Internet slowness

Since you have some layers network device involved.


1. i will try to replace any  faulty cat5 cables to see any better, if not start finding problem each edge

2. start with ISP start point, connnect your laptop directly with ISP Router and check is this better. ? check MTU ?

3. same behind router  -  and check Router has any high CPU or memory load ?

4, behind FW - check FW logs and cpu

5 lastly check behind switch -- again switch has any high CPU ?


post all the test informatiuon, and device model / code running so understand better ?

*** Rate All Helpful Responses ***

Re: Internet slowness

Hi Balaji,

1. Well I suspect the same and replacing the cables from switch to ISP circuit and also from firewall outside interface is going to be next option. Will try that and let you know.
2. As it is 24/7 working office getting an outage time is being very difficult. Also i am sure that there is no problem with MTU.
3.There is absolutely no high CPU or Memory utilization both in switch and in firewall. Also in router it is fine.

I will try to change the cables and see if there is any better pick up.
VIP Advisor

Re: Internet slowness

Please let us know how the things goes after you repalce cable. as other my mate pointed,


1. Do you have any monitoring system which monitors your WAN 20Meg pipe ?

2. if yes that is the utilisation on that time when the users reported slowness ?


we expect some inputs further to advise.


*** Rate All Helpful Responses ***
Hall of Fame Community Legend

Re: Internet slowness

Draw the network diagram.
We want to see how the network hangs.
What model of router?
VIP Mentor

Re: Internet slowness



on a side note, how many users do you have ? A 20 Meg connection is not much, especially if you have multiple users. I have a 50Mbps connection at home, just for myself, and even that is slow sometimes.

CreatePlease to create content
Content for Community-Ad
FusionCharts will render here