Asus DSL-AC88U and static IP

the-gog · 5 Aug 2017 at 16:46

This arrived this morning. An impressive piece of kit, except for one small flaw. I have a /29 of public IP addresses from my ISP. This works perfectly fine on both my Belkin F5D7633-4UK and Linksys WTR54GR ADSL2+ modems from 12 years ago. However, I can't find a way to specify to this Asus that its LAN IP should be ().().().217 on a subnet of 255.255.255.248 - it seem to only want to work on 192.168.1.1. As such, it's an expensive doorstop. Has anyone else managed to get it to work with a LAN IP assigned to a public range?

Richard

mmj_uk · 5 Aug 2017 at 18:42

I'm unfamiliar with DSL but under advanced settings there should be a LAN menu? but shouldn't anything going externally be on the WAN? (possibly showing my lack of DSL understanding there

)

eg. http://event.asus.com/2012/nw/dummy_ui/en/Advanced_LAN_Content.html

the-gog · 5 Aug 2017 at 18:52

Yes, there is. It's identical to that. Trouble is, each time I try to enter the public IP address I want it to sit on, it keeps saying "().().().217 is not a valid IP address!" (complete with exclamation mark)

I'm struggling to get Asus support to understand what I'm trying to achieve, ie having my LAN sat on un-NATed /29 public IP addresses. Might asking my ISP to change my default gateway static IP address to the same as the static WAN IP address help matters? I doubt it if I can't change my LAN IP to something other than 192.168.*.*

Richard

mmj_uk · 5 Aug 2017 at 19:39

Have you tried doing it on the WAN side instead of LAN? like I said I'm pretty clueless about DSL but with cable LAN applies to your own internal network, WAN is what connects to the wider network.

It might be worth downloading the latest firmware version and updating it as well.

the-gog · 5 Aug 2017 at 19:47

I'll have another fiddle tomorrow, but while I can manually change the WAN to my ().().().217 it still means my LAN can't be changed from 192.168.*.*

It's running the latest firmware. If Asus support can't suggest how to do it, the box is likely to have to be returned.

the-gog · 5 Aug 2017 at 19:50

Currently, my WAN is my LAN. My elderly Belkin modem gives me 5 un-NATted public IP addresses for computers, servers etc. This 2017 modem seemingly can't do that.

mmj_uk · 5 Aug 2017 at 20:16

Does the router have DHCP settings under LAN? with cable I have 1 public IP that connects via the WAN but I can connect 250 or so devices to the router on the LAN, that's what the internal 192.168.1.1 address range is for.

the-gog · 5 Aug 2017 at 20:20

Yes - I've tried changing that as well. I have a /29 subnet and not even one of those IP addresses is visible from the wider Internet using this modem.

mmj_uk · 5 Aug 2017 at 21:09

So am I right in thinking you can connect to the internet with the router but your problem is you want devices on your LAN to have public IP addresses and not be hidden behind the router?

the-gog · 5 Aug 2017 at 21:18

Correct. They're currently as visible to the outside world as any other router or server sat on the net and not behind NAT. One of my devices sat on public IP is an Asus RT-AC66U which then gives me a NAT subnet on which things like my TV, phone, PS3 sit, and also acts as a DLNA server. The RT-AC66U also acts as an Open VPN server so I can connect to my other computer through it via VNC. I've been doing this (with a different router prior to the RT-AC66U) since 2005 when my exchange first got ADSL.

mmj_uk · 5 Aug 2017 at 22:39

Ah I understand now, I totally misunderstood what you were trying to do but I'm still by no means an expert on networking so hopefully someone else can jump in to help.

My guess would be you might need to use the routing settings and redirect your public IP's to the internal address of the device so that it bypasses the firewall? you can set static internal IP addresses or just disable DHCP and assign addresses manually.

the-gog · 6 Aug 2017 at 13:00

mmj_uk said:
My guess would be you might need to use the routing settings and redirect your public IP's to the internal address of the device so that it bypasses the firewall? you can set static internal IP addresses or just disable DHCP and assign addresses manually.

I'm starting to think that this is how it's going to be possible, if so. I'll wait and see what Asus support tell me, but thought I'd ask here as well, in case anybody else has been in my situation and has managed to solve it. I've yet to take the plunge to VDSL until I have confidence that I can get this modem to behave the way I want it – if I have to reconfigure my network so that it at least sits behind one static IP, then so be it, at least until support is added in the firmware to route public IPs onto the LAN side.

Richard