Block Port 23 telnet

Discussions for BiPAC 8900 series: 8900AX-1600, 8900AX-2400, 8900X
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Citrus2
Posts: 3
Joined: Thu Sep 26, 2019 5:02 pm

Block Port 23 telnet

Post by Citrus2 » Thu Sep 26, 2019 5:18 pm

Hi
Does anyone know how to set up a rule to block Port 23 telnet?
I have a 8900ax 1600.
If anyone has an answer could they explain the whole process as it all looks to complicated to me
Its probably very obvious to other people : )
Looked in to port forwarding a bit. Does this need to cover my own IP address range on the router? One other forum said to use a fictitious one?
Any help would be marvellous : )
C.

billion_fan
Posts: 5201
Joined: Tue Jul 19, 2011 4:30 pm

Re: Block Port 23 telnet

Post by billion_fan » Fri Sep 27, 2019 9:19 am

Citrus2 wrote:
Thu Sep 26, 2019 5:18 pm
Hi
Does anyone know how to set up a rule to block Port 23 telnet?
I have a 8900ax 1600.
If anyone has an answer could they explain the whole process as it all looks to complicated to me
Its probably very obvious to other people : )
Looked in to port forwarding a bit. Does this need to cover my own IP address range on the router? One other forum said to use a fictitious one?
Any help would be marvellous : )
C.
Port 23 should be closed/stealthed by default, the only time it will be open is if you have enabled telnet within the remote access section or opened the port via the virtual server section, or UPNP has automatically opened this port (normally if UPNP has opened any ports they will be shown on the virtual server page)

As long as port 23 is not port forwarded (so no virtual server rule for port 23) it should show as un-open/closed/stealthed

You can use https://www.canyouseeme.org/ to check if port 23 is open

Citrus2
Posts: 3
Joined: Thu Sep 26, 2019 5:02 pm

Re: Block Port 23 telnet

Post by Citrus2 » Fri Sep 27, 2019 11:37 am

Hi
Thanks for the info
See attached
It seems a lot of people are getting this message after a router scan with ESET anti virus.
Some say it’s a different vulnerability to the normal port 23 telnet?
It feels a bit uncomfortable just leaving it without resolving the issue!
Any thoughts would be welcome : )
C2.
You do not have the required permissions to view the files attached to this post.

billion_fan
Posts: 5201
Joined: Tue Jul 19, 2011 4:30 pm

Re: Block Port 23 telnet

Post by billion_fan » Fri Sep 27, 2019 11:51 am

Citrus2 wrote:
Fri Sep 27, 2019 11:37 am
Hi
Thanks for the info
See attached
It seems a lot of people are getting this message after a router scan with ESET anti virus.
Some say it’s a different vulnerability to the normal port 23 telnet?
It feels a bit uncomfortable just leaving it without resolving the issue!
Any thoughts would be welcome : )
C2.
Telnet is enabled for internal network access only, for a external connections (which is what matters) it should be closed, hence running a online port scan will verify this. Most routers run telnet so it shouldn't be a issue (I'll check with our engineers if internal telnet access can be blocked/turned off)

Citrus2
Posts: 3
Joined: Thu Sep 26, 2019 5:02 pm

Re: Block Port 23 telnet

Post by Citrus2 » Fri Sep 27, 2019 2:59 pm

Brilliant.
Makes me feel better
C2

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