From Newsgroup: uk.telecom.broadband

We have just got a new Cityfibre FTTP connection and I'm trying to
work out the smoothest way of transferring our home LAN from the
existing Plusnet/FTTC connection to the new Cityfibre/FTTP.

The new connection is all up and running, I'm using IDNet as the ISP
and thus I have (as with Plusnet) a static IPV4 address.

I have SMTP and ssh servers running on one system on the LAN with the
(FTTC) router's firewall and port forwarding set up to allow outside connections (from specific places only) into that system. I have a
domain registered at Gandi Internet that I used for these.

I have an Asus DSL-AC68U router on the FTTC connection at the moment, I
have tried using that router's 'load balancing' to connect the new
FTTP connection as well. It works but seems to have issues which make
it a bit creaky, I suspect it may be something to do with web sites
getting confused by connections coming from different IPs.

I also have a new (to me) Asus RT-BE92U router which is configured for
the new FTTP connection.

So, to the question, can I connect both routers to my LAN at the same
time? Obviously I'd need to turn off DHCP one one router and
(probably) give it a fixed LAN IP, but would it then work?

I could then leave the old DSL-AC68U 'in control' but connect the
RT-BE92U as well. Then, when I change the zone file for my domain at
Gandi Internet, connections from outside will still succeed as the new
IP propagates. With both routers on the LAN I can easily configure
the new router to do the same things as the old router. Finally I can
switch DHCP from old to new router and, when all seems well, remove
the old router and discontinue the FTTC.

Does this sound a sensible approach or am I missing some obvious
problems? Is there a better way?
--
Chris Green
-+
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From Newsgroup: uk.telecom.broadband

Chris Green wrote:

can I connect both routers to my LAN at the same
time? Obviously I'd need to turn off DHCP one one router and
(probably) give it a fixed LAN IP, but would it then work?

yes, then when you're ready let DHCP give out the new router as default gateway ...

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.telecom.broadband

Chris Green wrote:

[snip]

I have an Asus DSL-AC68U router on the FTTC connection at the moment, I
have tried using that router's 'load balancing' to connect the new
FTTP connection as well. It works but seems to have issues which make
it a bit creaky, I suspect it may be something to do with web sites
getting confused by connections coming from different IPs.

That is exactly the problem with load balancing. In the past I used it
when I had two (slow) ADSL services - each about 2 Mbits/sec. My
solution was to identify the websites that had difficulty (generally
banks and the like) and specify a load balancing rule that such sites
would use only one connection. You could do the same.

Further, I imagine you will cancel the FTTC service within a matter of
weeks, so the problem will go away by itself.

The only thing you need to do is change your domain to point to the new
FTTP IP address. No need to change the router at all - unless you want
a feature only present on the new one.

Connecting both routers to the LAN at the same time in the way you
appear to be suggesting doesn't achieve anything useful, since all the outgoing traffic will leave via the router which is running DHCP because
it is the default gateway. Or the other router if your DHCP settings explicitly tell that to the clients. You **need** the load balancing function to control how the two WAN connections are to be used.

If the Asus DSL-AC68U router did not provide dual WAN you could in
principle use the new router connected to the LAN and specify it to be
the default gateway, but I can't see any purpose in that.
--
Graham J
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.telecom.broadband

Graham J <nobody@nowhere.co.uk> wrote:

Chris Green wrote:

[snip]

I have an Asus DSL-AC68U router on the FTTC connection at the moment, I have tried using that router's 'load balancing' to connect the new
FTTP connection as well. It works but seems to have issues which make
it a bit creaky, I suspect it may be something to do with web sites
getting confused by connections coming from different IPs.

That is exactly the problem with load balancing. In the past I used it
when I had two (slow) ADSL services - each about 2 Mbits/sec. My
solution was to identify the websites that had difficulty (generally
banks and the like) and specify a load balancing rule that such sites
would use only one connection. You could do the same.

I suspect nowadays it's going to be 'too complicated', with heavy use of Javascript, CDNs everywhere plus all the anti-AI checks. If nothing else
the list of rules is going to be massive (it's not just the name of the website, but a long list of hosts used by its CDN).

Further, I imagine you will cancel the FTTC service within a matter of weeks, so the problem will go away by itself.

Indeed, I'm not sure what you achieve by having dual WAN. Failover yes, but load balancing isn't going to do what you want unless you effectively tunnel both to a VPN endpoint that stitches them back together. Potentially two inbound routes, but that is less useful if you can't advertise routes in BGP
to your own IP range.

I suppose you could set up failover - dual WAN with all the traffic directed
to go over FTTP unless that is down, but allows inbound access from both
WANs. It would avoid problems with load balancing but offer a degree of resilience.

If your main router can do dual WAN I can't see of a situation where having
two routers makes any kind of sense.

Theo
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.telecom.broadband

Andy Burns <usenet@andyburns.uk> wrote:

Chris Green wrote:

can I connect both routers to my LAN at the same
time? Obviously I'd need to turn off DHCP one one router and
(probably) give it a fixed LAN IP, but would it then work?

yes, then when you're ready let DHCP give out the new router as default gateway ...

Good! Thank you.
--
Chris Green
-+
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.telecom.broadband

Theo <theom+news@chiark.greenend.org.uk> wrote:

Graham J <nobody@nowhere.co.uk> wrote:

Chris Green wrote:

[snip]

I have an Asus DSL-AC68U router on the FTTC connection at the moment, I have tried using that router's 'load balancing' to connect the new
FTTP connection as well. It works but seems to have issues which make
it a bit creaky, I suspect it may be something to do with web sites getting confused by connections coming from different IPs.

That is exactly the problem with load balancing. In the past I used it when I had two (slow) ADSL services - each about 2 Mbits/sec. My
solution was to identify the websites that had difficulty (generally
banks and the like) and specify a load balancing rule that such sites would use only one connection. You could do the same.

I suspect nowadays it's going to be 'too complicated', with heavy use of Javascript, CDNs everywhere plus all the anti-AI checks. If nothing else
the list of rules is going to be massive (it's not just the name of the website, but a long list of hosts used by its CDN).

Further, I imagine you will cancel the FTTC service within a matter of weeks, so the problem will go away by itself.

Indeed, I'm not sure what you achieve by having dual WAN. Failover yes, but load balancing isn't going to do what you want unless you effectively tunnel both to a VPN endpoint that stitches them back together. Potentially two inbound routes, but that is less useful if you can't advertise routes in BGP to your own IP range.

I suppose you could set up failover - dual WAN with all the traffic directed to go over FTTP unless that is down, but allows inbound access from both WANs. It would avoid problems with load balancing but offer a degree of resilience.

If your main router can do dual WAN I can't see of a situation where having two routers makes any kind of sense.

Two routers isn't intended to be a permanent setup, it just that I
want to handle the change of IP for the domain.
--
Chris Green
-+
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.telecom.broadband

Graham J <nobody@nowhere.co.uk> wrote:

Chris Green wrote:

[snip]

I have an Asus DSL-AC68U router on the FTTC connection at the moment, I have tried using that router's 'load balancing' to connect the new
FTTP connection as well. It works but seems to have issues which make
it a bit creaky, I suspect it may be something to do with web sites
getting confused by connections coming from different IPs.

That is exactly the problem with load balancing. In the past I used it
when I had two (slow) ADSL services - each about 2 Mbits/sec. My
solution was to identify the websites that had difficulty (generally
banks and the like) and specify a load balancing rule that such sites
would use only one connection. You could do the same.

Yes, I remember doing that a long time ago for some reason (many
years). I did what you say for a few banks. It looks as if more web
sites are applying the same sort of rules now.

Further, I imagine you will cancel the FTTC service within a matter of weeks, so the problem will go away by itself.

True, but the delays/failures are annoying!

The only thing you need to do is change your domain to point to the new
FTTP IP address. No need to change the router at all - unless you want
a feature only present on the new one.

I could continue with the old router but it will soon run out of
support from asuswrt-merlin so I'll need to move the the newer on some
time.

Connecting both routers to the LAN at the same time in the way you
appear to be suggesting doesn't achieve anything useful, since all the outgoing traffic will leave via the router which is running DHCP because
it is the default gateway. Or the other router if your DHCP settings explicitly tell that to the clients. You **need** the load balancing function to control how the two WAN connections are to be used.

Yes, I realise that. It's the **incoming** connections that I'm
concerned about during the changeover. I want these to work whichever
router they come through, then when the change of IP for my domain has propagated I can stop DHCP in the old router and start DHCP in the new
router.
--
Chris Green
-+
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.telecom.broadband

Chris Green wrote:

[snip]

Yes, I realise that. It's the **incoming** connections that I'm
concerned about during the changeover. I want these to work whichever
router they come through, then when the change of IP for my domain has propagated I can stop DHCP in the old router and start DHCP in the new router.

Use one router, with dual WAN. Configure failover - this means that
almost all outgoing traffic will use whichever you have specified as
primary, except if that connection fails.

Unsolicited incoming traffic arriving on the secondary WAN port (such as
for a web server or SMTP server, before your domain IP change
propagates) will be routed via your "open ports" or "port redirection" configuration (whatever it is called in your router) to the LAN IP you specify. Replies to that traffic will leave your router via the same
route that it arrived by, because of the way that the port opening works.

This is all achieved within the NAT mechanism: replies to outgoing
traffic are returned to the LAN IP of the source: unsolicited incoming traffic is blocked unless you make specific exceptions, in which case
the replies are sent out via the same path that they arrived.
--
Graham J
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.telecom.broadband

On 22/10/2025 12:41, Chris Green wrote:

We have just got a new Cityfibre FTTP connection and I'm trying to
work out the smoothest way of transferring our home LAN from the
existing Plusnet/FTTC connection to the new Cityfibre/FTTP.

The new connection is all up and running, I'm using IDNet as the ISP
and thus I have (as with Plusnet) a static IPV4 address.

I have SMTP and ssh servers running on one system on the LAN with the
(FTTC) router's firewall and port forwarding set up to allow outside connections (from specific places only) into that system. I have a
domain registered at Gandi Internet that I used for these.

I have an Asus DSL-AC68U router on the FTTC connection at the moment, I
have tried using that router's 'load balancing' to connect the new
FTTP connection as well. It works but seems to have issues which make
it a bit creaky, I suspect it may be something to do with web sites
getting confused by connections coming from different IPs.

I also have a new (to me) Asus RT-BE92U router which is configured for
the new FTTP connection.

So, to the question, can I connect both routers to my LAN at the same
time? Obviously I'd need to turn off DHCP one one router and
(probably) give it a fixed LAN IP, but would it then work?

I could then leave the old DSL-AC68U 'in control' but connect the
RT-BE92U as well. Then, when I change the zone file for my domain at
Gandi Internet, connections from outside will still succeed as the new
IP propagates. With both routers on the LAN I can easily configure
the new router to do the same things as the old router. Finally I can
switch DHCP from old to new router and, when all seems well, remove
the old router and discontinue the FTTC.

Does this sound a sensible approach or am I missing some obvious
problems? Is there a better way?

Couldn't you achieve what you're trying to do solely using DNS?

e.g. for SMTP you could create two MX records with Priority set to your
City Fibre A record and lesser priority assigned to the Plusnet IP.

Then wait adequate time for all DNS servers to propagate, swap all your
kit across to the City Fibre connection and then delete the Plusnet MX
record.

Doesn't work quite as well for the SSH servers mind you. You could round
robin two A records but it's imperfect. Who/what accesses these servers though? If they're just for your use then I can't imagine it's too much
of a problem to make note of a couple of different IP's whilst the
transition is underway? Or maybe set up a new subdomain for the City
Fibre IP, let it propagate, and reconfigure anything that's connecting
to the SSH servers at the time you switch kit across? You can then take
your time changing the IP of the original domain and reverting the
config if it's important to you.
--
Bob Pullen
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.telecom.broadband

Bob Pullen <me@privacy.net> wrote:

On 22/10/2025 12:41, Chris Green wrote:

We have just got a new Cityfibre FTTP connection and I'm trying to
work out the smoothest way of transferring our home LAN from the
existing Plusnet/FTTC connection to the new Cityfibre/FTTP.

The new connection is all up and running, I'm using IDNet as the ISP
and thus I have (as with Plusnet) a static IPV4 address.

I have SMTP and ssh servers running on one system on the LAN with the (FTTC) router's firewall and port forwarding set up to allow outside connections (from specific places only) into that system. I have a
domain registered at Gandi Internet that I used for these.

I have an Asus DSL-AC68U router on the FTTC connection at the moment, I have tried using that router's 'load balancing' to connect the new
FTTP connection as well. It works but seems to have issues which make
it a bit creaky, I suspect it may be something to do with web sites
getting confused by connections coming from different IPs.

I also have a new (to me) Asus RT-BE92U router which is configured for
the new FTTP connection.

So, to the question, can I connect both routers to my LAN at the same
time? Obviously I'd need to turn off DHCP one one router and
(probably) give it a fixed LAN IP, but would it then work?

I could then leave the old DSL-AC68U 'in control' but connect the
RT-BE92U as well. Then, when I change the zone file for my domain at
Gandi Internet, connections from outside will still succeed as the new
IP propagates. With both routers on the LAN I can easily configure
the new router to do the same things as the old router. Finally I can switch DHCP from old to new router and, when all seems well, remove
the old router and discontinue the FTTC.

Does this sound a sensible approach or am I missing some obvious
problems? Is there a better way?

Couldn't you achieve what you're trying to do solely using DNS?

e.g. for SMTP you could create two MX records with Priority set to your
City Fibre A record and lesser priority assigned to the Plusnet IP.

Then wait adequate time for all DNS servers to propagate, swap all your
kit across to the City Fibre connection and then delete the Plusnet MX record.

Doesn't work quite as well for the SSH servers mind you. You could round robin two A records but it's imperfect. Who/what accesses these servers though? If they're just for your use then I can't imagine it's too much
of a problem to make note of a couple of different IP's whilst the transition is underway? Or maybe set up a new subdomain for the City
Fibre IP, let it propagate, and reconfigure anything that's connecting
to the SSH servers at the time you switch kit across? You can then take
your time changing the IP of the original domain and reverting the
config if it's important to you.

Thanks Bob.

In the event I just configured the new router with the same IP etc. as
the old one, set the TTL for the domain to 300 (five minutes) and then disconnected the old router, connected the new one and switched the A
record. It worked with hardly a murmur.

That reminds me, I must the TTL back to something more sensible like
3600.
--
Chris Green
-+
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.telecom.broadband

On 25/10/2025 16:37, Chris Green wrote:

In the event I just configured the new router with the same IP etc. as
the old one, set the TTL for the domain to 300 (five minutes) and then disconnected the old router, connected the new one and switched the A
record. It worked with hardly a murmur.

That reminds me, I must the TTL back to something more sensible like
3600.

Didn't you have things that need to be at the same address on your new
LAN so that port forwarding will still reach them?
--
Brian Gregory (in England).
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.telecom.broadband

Brian Gregory <void-invalid-dead-dontuse@email.invalid> wrote:

On 25/10/2025 16:37, Chris Green wrote:

In the event I just configured the new router with the same IP etc. as
the old one, set the TTL for the domain to 300 (five minutes) and then disconnected the old router, connected the new one and switched the A record. It worked with hardly a murmur.

That reminds me, I must the TTL back to something more sensible like
3600.

Didn't you have things that need to be at the same address on your new
LAN so that port forwarding will still reach them?

Yes, a couple, well one actually, same LAN IP for both SMTP and ssh. I remembered to configure the new router to do the port forwarding so
that worked straight away. However I forgot to configure the DHCP to
give the ssh/smtp server its fixed address, so 24 hours later that
system suddenly 'disappeared' when it renewed its address. It took me
a few minutes to realise what had happened but was a very simple fix
to do. :-)
--
Chris Green
-+
--- Synchronet 3.21a-Linux NewsLink 1.2