Log In

Come Join Us!

Are you a
Computer / IT professional?
Join Tek-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here




We have a site to site VPN running over a DSL line between two SonicWALL appliances. A while back we began having issues at the remote site with domain logons taking close to 20 minutes. After much searching I found that the issue was able to be resolved by reducing the MTU to 1420 across the network. I changed the MTU setting on the SonicWALL and then went through and set the MTU on all the machines in the network to 1420 as well thinking that this could possibly make for smoother communication across the board. What I now find strange is that when I test the network using ping -f -1 1420 It now says this has to be fragmented and will not send a packet larger than 1392. If I lower the MTU to 1392 then I can't send a packed larger than 1364. In other words for some reason I can not send a packet any more than 28 less than whatever I set the MTU. What am I missing here? I am not really an expert on this. Is this normal or is there something else that I should be setting? I am not currently having any serious issues although the communication across the network at times is not that smooth in spite of the fact that it is a very small network and really that congested. I was hoping to get things running smoother though.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Tek-Tips Forums free from inappropriate posts.
The Tek-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Tek-Tips forums is a member-only feature.

Click Here to join Tek-Tips and talk with other members!

Close Box

Join Tek-Tips® Today!

Join your peers on the Internet's largest technical computer professional community.
It's easy to join and it's free.

Here's Why Members Love Tek-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close