In reply to a post by Chrysalis:

ok so confirmed working on merlin, and you didnt need to reestablish ppp right?

Yep.

the startup thing problem is they likely to execute before the network is up but merlin allows to set scripts to run when certian events happens if I am right you can add the script to run when the network is started, or better after the network is started.

I think I've got to enable the jffs filesystem and I can put a custom script there.

However I found two websites that I use that wouldn't respond after the change, so I've backed out for now until I can work out what I've done wrong

my router self rebooted yesterday, I ran the ifconfig commands but when I changed the mtu size of eth2 it caused ppp to drop and recconect at the higher mtu. so in my case if ppp is already up it forces it it drop to change the setting.

of course my router rebooting itself is the bigger problem, I have just enabled jffs myself to get some persistent logging.

what are the 2 websites? I can test. PM me if private.