I am also experiencing this issue (intermitent text failures). It happened again yesterday afternoon. I sent two text messages from my Vz phone (Droid 3) on the extender to another Vz phone about 15 miles away - and the messages were never received (Droid 2). I did not receive a send failure notice on my phone.
I have previously had instances where I send messages from my phone on the extender and the phone says they failed to send, but actually did send. Receipient then gets two copies.
Given the choice of the recipient getting two copies, and no copies - I would gladly take two. The problem is when a text is getting dropped in the network, you have no way of knowing without contacting the recipient and asking "Did you get my text".
I have tried the Network Extender on multiple Internet providers, and verified there are no firewall issues with all the destination IPs and ports.
As instructed by Verizon support, I have also updated my PRL (*228) several times over the last 6 months, and that hasn't helped.
Not sure if this is related or not, but sometimes my phone shows a 1X signal instead of a 3G signal, even when it's 4 feet away from the network extender. I will try to determine whether the texting failures are on 1X or 3G in case that helps narrow down the issue.
Because lack of texting reliability is a safety concern, I am almost to the point of putting a network sniffer on the ethernet segment to try to look for network errors where Verizon IPs aren't responding, DNS isn't getting resolved quick enough, etc.
