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mdella 10-15-2018 12:03 AM

Forcing an IPv4 or IPv6 connection using SecureCRT
So I've been doing a tremendous amount of work in areas where IPv4 address space has been depleted. As such I've started converting many of the US resources I manage to be "dual/stack". Unfortunately in do so, many of the DNS records start having "A" and "AAAA" records for the same name.

There are times when IPv4 or IPv6 stacks are broken between myself and the destination where I want to force the connection to use one protocol over the other. With "ssh" you use the "-4" or "-6" options to force ssh to use one or the other protocol. I have been unable to find any service similar on SecureCRT. This has led me to having to log into a third party machine, do a dig for the IPv4 address, then temporarily replace the machine name on SecureCRT with a hard coded IP address until I can fix the problem or work around it. Often I'm finding that I'm not moving back to using DNS (which with AWS and virtual machines constantly changing their public IP addresses) which is problematic in many ways.

Is it possible to add a checkbox that says "use IPv4" or "use IPv6" or "prefer IPv4 over IPv6" if the other two boxes are checked? (total of three check boxes I suppose). I'd assume the default configuration for any houst would have the first two check boxes checked and the third not checked. This way I can go in and change things as I go.


bgagnon 10-15-2018 09:46 AM

Hi Marcos,

I have added this thread to the following feature requests in our product enhancement database:
  • Try IPv4 if IPv6 timeout causes connection to fail
  • Option to set which IP type to use when both IPv4 and IPv6 are available
Should a future release of SecureCRT include either feature, notification will be posted here.

If you prefer direct email notification, send an email to and include "Feature Request - Forum Thread #13289" in the subject line or use this form from the support page of our website.

As a note, Microsoft provides a fairly easy method to accomplish this preference switch by way of a registry modification as explained in this tip.

mdella 08-08-2020 10:59 AM

Still looking to force IPv4 or IPv6 connections
So the problem with the tip is that its for my entire laptop which I do have several IPv6 connections going to other sites. I'm trying to force various protocols so that I can do maintenance on the opposite protocol on a router without disconnecting myself.

Now I'm working with a MacOS device and have the same problem as the original posting. To date I've been manually looking up IPs and creating duplicate entries for all my connections, but now I have three entries for just about every device I connect to (one by name, one by manual IPv4, one by manual IPv6, both of the last I have to look up and if they change, I have to notice and look up again...)

I'm guessing that this never made it to the "to-do" this...


Maureen 08-10-2020 12:06 PM


Thanks for following up on this request. It's something we're planning to look into for an upcoming release of SecureCRT. We'll post something here when we have something for you to try.


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