C1111-4P Router no ISP access on LAN

[Beer Money]

Good day… I’m a complete hack, aka novice, when it comes to complex networks like I have, but I do appreciate the ability to configure a great network and learn something in the process.  That being said, please be very specific in your response as this is way above my skill level.  

I recently upgraded my router from the RV340 to the C1111-4P as some of my new Sonos speakers weren’t connecting to the network due to the lack of proxy support on the 340.  Here’s the equipment that currently makes up my network.  

C1111-4P Router

Three SG350-10P Switches. One of the switches are connected directly to router in the network closet and the other two switches are connected to the first one off of the router.  

Two 240AC access points one is connected to the switch off the router, the other is at a distant switch. 

My issue is that I can’t access the ISP from the LAN network.  The router can access it from the WAN troubleshooting shooting tool on the routers WebUi.  I can access the router via console using PuTTY so if there’s anything I can do or provided via the console, please be very specific and I shouldn’t have an issue.  Thank you for all your help in advance, I greatly appreciate it!  I’m sure I’ll need more as I get this router dialed in!

[Joseph W. Doherty]

Your router will be the DHCP server for your interior network.

The WAN interface will be a DHCP client of your ISP.

Hopefully, the "import" statement will copy some ISP DHCP data, like DNS servers, from them, and pass that along to your DHCP interior clients.  I.e. this so you don't need to maintain DNS server IPs in your DHCP pool.

[Beer Money]

Good day!   I know have internet access on the LAN!   Now on to sort of the Sonos settings on a different thread.  Thank you for your help, I greatly appreciate it!  

[Joseph W. Doherty]

So glad to read that because your configuration appeared it should work.

[Beer Money]

Actually, I think I found it.  Here's what I see.  

Router#show config
Using 3056 out of 33554432 bytes
!
! Last configuration change at 15:19:41 GMT Sat Jun 28 2025
!
version 17.5
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
service call-home
platform qfp utilization monitor load 80
platform punt-keepalive disable-kernel-core
platform hardware throughput crypto 50000
!
hostname Home
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
clock timezone GMT -5 0
!
!
!
!
!
!
!
ip domain name Home
ip dhcp excluded-address 192.168.1.1 192.168.1.5
!
ip dhcp pool WEBUIPool
network 192.168.1.0 255.255.255.0
default-router 192.168.1.1
dns-server 8.8.8.8 4.2.2.2
!
!
!
login on-success log
!
!
!
!
!
!
!
subscriber templating
multilink bundle-name authenticated
!
!
!
crypto pki trustpoint TP-self-signed-1615506262
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-1615506262
revocation-check none
rsakeypair TP-self-signed-1615506262
!
crypto pki trustpoint SLA-TrustPoint
enrollment pkcs12
revocation-check crl
!
!
crypto pki certificate chain TP-self-signed-1615506262
certificate self-signed 01 nvram:IOS-Self-Sig#2.cer
crypto pki certificate chain SLA-TrustPoint
certificate ca 01 nvram:CiscoLicensi#1CA.cer
!
!
license udi pid C1111-4PWB sn FGL2636LC2Q
memory free low-watermark processor 70642
!
diagnostic bootup level minimal
!
spanning-tree extend system-id
!
username Home privilege 15 secret 9 $9$tu2dK5HyyrXeF.$WcL4/rSO0xy5MsDiY.1uQiSw1/Tcc90xU0LCpKpKNPk
!
redundancy
mode none
!
!
vlan internal allocation policy ascending
!
!
!
!
!
!
interface GigabitEthernet0/0/0
description ISP-Router
ip address dhcp
ip nat outside
negotiation auto
!
interface GigabitEthernet0/0/1
ip address dhcp
negotiation auto
!
interface GigabitEthernet0/1/0
switchport mode access
!
interface GigabitEthernet0/1/1
switchport mode access
!
interface GigabitEthernet0/1/2
!
interface GigabitEthernet0/1/3
!
interface Wlan-GigabitEthernet0/1/4
!
interface Vlan1
ip address 192.168.1.1 255.255.255.0
ip nat inside
no autostate
!
ip http server
ip http authentication local
ip http secure-server
ip forward-protocol nd
ip dns server
ip nat inside source list 10 interface GigabitEthernet0/0/0 overload
ip nat inside source list 197 interface GigabitEthernet0/0/1 overload
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0/1
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0/1 dhcp
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0/0 dhcp
!
!
!
ip access-list standard 10
10 permit 192.168.1.0 0.0.0.255
ip access-list extended 197
10 permit ip any any
!
!
!
control-plane
!
!
line con 0
transport input none
stopbits 1
line vty 0 4
login
length 0
transport input ssh
line vty 5 14
login
transport input ssh
!
call-home
! If contact email address in call-home is configured as sch-smart-licensing@cisco.com
! the email address configured in Cisco Smart License Portal will be used as contact email address to send SCH notifications.
contact-email-addr sch-smart-licensing@cisco.com
profile "CiscoTAC-1"
active
destination transport-method http
!
!
!
!
!
!
end

[Beer Money]

M02@rt37 keep in mind, it's not currently connected to the modem or any other network gear, as you might be able to tell.  

*edit*  

I could connect it to an existing switch to create a network for troubleshooting, but it's currently set to the same IP address as the RV340 router which will likely cause issues.  

[Joseph W. Doherty]

Physically, you just pulled the RV340 and basically connected the C1111 just as the RV had been connected?  Have you tried reconnecting the RV to determine if all works as it did?

Any chance obtaining a copy of the RV config?  (Actually, I don't know if the RV can provide a text config copy.). Also, a copy of C1111 config?

Cannot say for sure with the RV or C1111, but home oriented Internet routers, by default, usually will connect to a home type ISP and support one private inside network, with DHCP, and NAT/PAT(+).

"Professional" grade routers usually need to be configured to do the same (and historically have been weak on PAT+ [+ being fixups beyond just port mappings]).

As far as specific configs are concerned, probably could provide a generic one, but without SG configs, unless we know RV config (or SG configs), cannot assure a generic C1111 will work for you.   Although, hopefully unlikely, believe the SGs are L3 switches, so how they've been working with the RV, can be crucially important.

[Beer Money]

Physically, you just pulled the RV340 and basically connected the C1111 just as the RV had been connected? Yes, that's correct.  After I completed the initial set up of the C1111.   Have you tried reconnecting the RV to determine if all works as it did? Yes, the network works as expected when I reconnect the RV340.  

Any chance obtaining a copy of the RV config?  (Actually, I don't know if the RV can provide a text config copy.). Also, a copy of C1111 config? I certainly can, I apologize but very new to this.  Do mind providing the command to get that?  Thank you!  

Cannot say for sure with the RV or C1111, but home oriented Internet routers, by default, usually will connect to a home type ISP and support one private inside network, with DHCP, and NAT/PAT(+). That's what I expected, but wasn't the case with the C1111.  

"Professional" grade routers usually need to be configured to do the same (and historically have been weak on PAT+ [+ being fixups beyond just port mappings]).

As far as specific configs are concerned, probably could provide a generic one, but without SG configs, unless we know RV config (or SG configs), cannot assure a generic C1111 will work for you.   Although, hopefully unlikely, believe the SGs are L3 switches, so how they've been working with the RV, can be crucially important.  The C1111 came recommended for the issues I was having with Sonos, the lack of DHCP Proxy.  

[Joseph W. Doherty]

The C1111 came recommended for the issues I was having with Sonos, the lack of DHCP Proxy.

Taking the last sentence first, why does the Sonos need a router with DHCP proxy capability?

The reason I ask, generally a router that supports DHCP proxy is in the situation where the DHCP server doesn't have a direct connection to the subnet requesting DHCP addressing; which is usually unusual in home networks because often the gateway router is the only router and often the DHCP server too.

In other words, before considering using a C1111, we should really understand the Sonos issue; at the very least, as it may require manual C1111 configuration.

[Beer Money]

Taking the last sentence first, why does the Sonos need a router with DHCP proxy capability?  From my extremely limited understanding of it, the Sonos Sub 4, when paired with the Sonos Arc Ultra, needs the proxy functionality.  Which seems like a step in the wrong direction since my Sub 3 doesn't need it when it's paired with the Sonos Arc.  

[Joseph W. Doherty]

---

@Beer Money wrote:

Taking the last sentence first, why does the Sonos need a router with DHCP proxy capability?  From my extremely limited understanding of it, the Sonos Sub 4, when paired with the Sonos Arc Ultra, needs the proxy functionality.  Which seems like a step in the wrong direction since my Sub 3 doesn't need it when it's paired with the Sonos Arc.  

---

Could you provide an on-line documentation reference for the Sonos hardware.

BTW, DHCP network hosts, shouldn't "need" DHCP proxy, as the service should be "invisible" to them.  Also, BTW, the prior sentence doesn't mean, you network may not need a DHCP proxy, just again, it should be "invisible" to a typical DHCP client.

Anyway, if you're unfamiliar with how DHCP works, in brief (and high level):

When a DHCP client comes up on the network, it broadcasts a request for a DHCP IP.

If there's a DHCP server interface on the same L2 broadcast domain, as the requesting client, it will "see" the request, and if the server has an available IP, it offers that IP to the client, which when the client receives it, the client can choose to attempt to use.

If the DHCP server doesn't have an interface on the same L2 broadcast domain, and as broadcasts generally are not passed between subnets, a router with an interface on the same L2 broadcast domain, can be configured to "repackage" the DHCP request and send it to known DHCP server(s), which again, if they have an available IP in the subnet, will offer a DHCP IP to the client.  From the perspective of the DHCP client, it again will receive a DHCP IP, which it can chose to attempt to use.

Again, the client shouldn't really care whether the DHCP server has a local subnet connection or not, it just cares whether it's offered a possible IP to use.

So, again, the first question is, why does the Sonos care?  Second question, what's the DHCP server and is it on a another subnet?

To put this another way, without understanding why the Sonos doesn't work with the RV, there's a really good chance it won't work on the C1111 either, at least with a basic configuration.  (That's not to say, moving to the C1111 might offer other benefits over the RV, but as you've already seen, it likely requires configuration for the other devices that had been working with the RV.  Also, some devices, not too commonly, want other information passed to them, from a DHCP server, in conjunction with an IP.  Perhaps this is the issue with the Sonos devices.  If the latter is the case, possibly the C1111 has the capability to provide such additional information and the RV does not.)

[Beer Money]

Here's are some excerpts from the Sonos support community.  

Corry P

Sonos Staff

"The Sub is the only device encountering this issue because it is the only device trying to connect via a wireless backhaul created by the Arc Ultra, though it will not be if you try to add surrounds. I did not say that there was anything wrong with the router, just that it does not meet our requirements (unless ethernet is used).

I hope this helps."

"

The router needs to support DHCP Proxy - though, I don’t think this is something that tends to get advertised. Most routers do support it - I only know of Cisco and Asus not doing so (though I believe with Asus it can be worked-around).

You can see our hardware incompatibility list here: Incompatible network hardware. Cisco is listed there, but only multiple ethernet connections to Sonos is listed as an issue - possibly because the workaround for your issue is to use a single ethernet connection.

Incidentally, the last person I help that had this issue was able to bypass it after disabling QoS (Quality of Service) functionality in their router’s setting, though that was with Asus - perhaps you will have the same luck? I hope so.

I hope this helps."

[Joseph W. Doherty]

---

@Beer Money wrote:

Here's are some excerpts from the Sonos support community.  

Corry P

Sonos Staff

"The Sub is the only device encountering this issue because it is the only device trying to connect via a wireless backhaul created by the Arc Ultra, though it will not be if you try to add surrounds. I did not say that there was anything wrong with the router, just that it does not meet our requirements (unless ethernet is used).

I hope this helps."

"

The router needs to support DHCP Proxy - though, I don’t think this is something that tends to get advertised. Most routers do support it - I only know of Cisco and Asus not doing so (though I believe with Asus it can be worked-around).

You can see our hardware incompatibility list here: Incompatible network hardware. Cisco is listed there, but only multiple ethernet connections to Sonos is listed as an issue - possibly because the workaround for your issue is to use a single ethernet connection.

Incidentally, the last person I help that had this issue was able to bypass it after disabling QoS (Quality of Service) functionality in their router’s setting, though that was with Asus - perhaps you will have the same luck? I hope so.

I hope this helps."

---

The information, itself, wasn't very helpful (sorry), but the link to the Sonos was somewhat more helpful.

Firstly, the RV series is noted it should work if RSTP is enabled (interesting "work around").

From reading a bit about the Arc Ultra and Sub 4, both support either wired or wi-fi connectivity.  Their documentation isn't too clear, especially mention of (one of the products?) mentioning (?) it can create its own private wi-fi network.

Were you planning on using wired or wireless connectivity?

If you want to go wireless, what's the AP, the RV340 or C1111?

[Beer Money]

The goal is to be wireless through the AC240 that's connected to one of the SG350's