DHCP works, but NO Internet

Maga · October 5, 2024, 2:19pm

Hello. I am studying and playing Mikrotik hEX S at the company where I work.
My Senior gave me a task: Connect the Internet via Mikrotik, but without a Bridge.
DHCP is working. I got IP, Subnet Mask, Gateway, etc. on PC via DHCP. But no access to the internet.

Can anyone help me? I would appreciate it.
Thank you very much.

I removed the Default configuration on the first start on Mikrotik.

PC connected to Mikrotik via ether2 and ether1 is my WAN. By the way, the LAN which going to ether1 as WAN is coming from a Switch, and when I connect this cable directly to the PC from the Switch I get Static 192.168.88.103 IP address/Gateway: 192.168.88.1. So I can access the internet.

So
I created a 192.168.4.0/24 IP Address List on ether4 Interface.
I created an IP Pool 192.168.4.2-192.168.4.254.
I created a DHCP on the ether4 interface:
DHCP Address Space: 192.168.4.0/24
Gateway for DHCP Server: 192.168.4.1
DNS: 1.1.1.1
I created NAT rule on ether1 interface:
chain: srcnat
Out. Interface: ether1
Action: masquerade

MyConfig:

# 1970-01-02 03:24:24 by RouterOS 7.16
# software id = WUW1-P1FX
#
# model = RB760iGS
# serial number = HET097BM3TD
/ip pool
add name=dhcp_pool0 ranges=192.168.4.2-192.168.4.254
/ip dhcp-server
add address-pool=dhcp_pool3 interface=ether4 name=dhcp1
/ip neighbor discovery-settings
set discover-interface-list=!dynamic
/ip address
add address=192.168.4.0/24 interface=ether4 network=192.168.4.0
add address=192.168.88.103/24 interface=ether1 network=192.168.88.0
/ip dhcp-server network
add address=192.168.4.0/24 dns-server=1.1.1.1 gateway=192.168.4.1
/ip firewall nat
add action=masquerade chain=srcnat out-interface=ether1
/system note
set show-at-login=no

IP route print:

DST-ADDRESS      GATEWAY  DISTANCE
DAc 192.168.4.0/24   ether4          0
DAc 192.168.88.0/24  ether1          0

Winbox screen:
https://ibb.co/GtTV61Y

My connections:
https://ibb.co/PZHkr6v
https://ibb.co/Pmb540x

I tried learning to use Port Isolation, Static Route, and Add New ARP. But I failed, I think maybe one of these I should use or maybe not.
Can anyone help me? I would appreciate it.
Thank you very much.

jvanhambelgium · October 5, 2024, 5:21pm

IP route print:
Code: Select all

DST-ADDRESS GATEWAY DISTANCE
DAc 192.168.4.0/24 ether4 0
DAc 192.168.88.0/24 ether1 0

You do not have a static default-route and that is the reason why it does not work.
Add a static route 0.0.0.0/0 pointing to the next hop “192.168.88.1” across interface ether1

mkx · October 5, 2024, 7:51pm

Address on “LAN” side is wrong:

/ip address
add address=192.168.4.0/24 interface=ether4 network=192.168.4.0

Address should be 192.168.4.1/24 instead.

anav · October 5, 2024, 8:28pm

What is the purpose of connecting without a bridge???
Easy to assign ports to a single subnet no bridge, but what is the fun in that??

Maga · October 5, 2024, 9:42pm

Because the Task was like this:
Configure Mikrotik for:
100 IP cameras have to connect to ether2 via NVR
20 IP Tel have to connect to ether3 via ??
20 PC have to connect to ether4 via ??
5 Access points have to connect to ether5 via ??

Not Bridge? Because each network should not see each other.

I just wanted to understand the logic for one of these, then I can apply it to the rest.

Maga · October 5, 2024, 9:44pm

Thank you very much! I corrected it, so I don’t have to change Gateway in DHCP, even DHCP Gateway and Address is same?

Maga · October 5, 2024, 10:16pm

.aaa

Maga · October 5, 2024, 10:47pm

Thank you for your attention!
https://hizliresim.com/sdg3yy8
Gateway should be IP address or ether port?
Because both didn’t work.

jvanhambelgium · October 6, 2024, 6:07am

192.168.88.1 is OK as next-hop.
The Mikrotik will find it.
So correcting the mentioned 192.168.4.x on the INTERFACE itself combined with a correct static-route should get it working I guess.

Maga · October 6, 2024, 8:51am

Thanks for your attention again!

I changed Address on Address list from 192.168.4.0/24 to 192.168.4.1/24:
https://hizliresim.com/gd1nlr0

Does it matter if Gateway in DHCP is 192.168.4.1 or 192.168.4.2? It shouldn’t be the same as Address on the Adress list or not.:
https://hizliresim.com/qa7p63a

DHCP works fine but there is no Internet Access:
https://hizliresim.com/3och7bd

Maybe something is wrong with DNS in DHCP. It should be 1.1.1.1 or the IP comes to the PC when I connect the ethernet cable from the router to the PC.:
https://hizliresim.com/1v6smfq

For the Static IP Route, you mentioned before you said 192.168.88.1 why? Because it is the default IP address for MikroTik or 192.168.88.1 is the Gateway I get from Switch’s DHCP that connected to Mikrotik’s ether1?

Let’s say I did the right configuration after that I should Reboot Mikrotik or Disable/Enable the Ethernet Adapter on the PC or what?

Thank you!

Maga · October 6, 2024, 9:01am

GOOD NEWS!!

I wrote in cmd
ipconfig /release
ipconfig /renew

After that PC shows Access to the Internet. But I enter YouTube.com on browser it keeps loading and after that pooh Internet Acces lost.

When I repeated the process it gave the same result.s

Maga · October 6, 2024, 9:26am

https://hizliresim.com/grjucg0

jvanhambelgium · October 6, 2024, 10:03am

Does it matter if Gateway in DHCP is 192.168.4.1 or 192.168.4.2? It shouldn’t be the same as Address on the Adress list or not.:
https://hizliresim.com/qa7p63a

Offcourse this matter. This is KEY. The value of gateway must be the same as the IP of the interface !
So in your case 192.168.4.1
Otherwise no PC will find its way out of that subnet…

jvanhambelgium · October 6, 2024, 10:05am

What about that DNS .
Is see 192.168.1.75 assigned as DNS-server ?? Where is it ?
Try to assign 1.1.1.1 (or 8.8.8. in the DHCP-settings for clients to start with.
Can you perform a basic lookup ?
So open CMD-prompt, and try “ping www.youtube.com” ?? What does it do / say ???

Maga · October 6, 2024, 4:42pm

So open CMD-prompt, and try “ping www.youtube.com” ?? What does it do / say ???
cmd screenshot → https://hizliresim.com/ipfbd83

I fixed Gateway and DNS. But still the same issue:
I wrote in cmd ipconfig /release and ipconfig /renew, so Internet access comes(but very slow, I tried 5 times, and at once YouTube opened very slowly) after a 10-second boom Internet Acces lost.
Pics:
https://hizliresim.com/ot3lv5l
10 sec later:
https://hizliresim.com/dcgnf6u

Maga · October 6, 2024, 4:45pm

Could you answer these two, please? I read tons of Mikrotik forums, but can’t find these specific situations.

For the Static IP Route, you mentioned before you said 192.168.88.1 why? Because it is the default IP address for MikroTik or 192.168.88.1 is the Gateway I get from Switch’s DHCP that connected to Mikrotik’s ether1?
Let’s say I did the right configuration after that I should Reboot Mikrotik or Disable/Enable the Ethernet Adapter on the PC or what?

jvanhambelgium · October 6, 2024, 6:32pm

I understood earlier in your posts that your "ether1" is your ISP "uplink" AND if you pull out the cable out of your Mikrotik router and put it on a PC it receives via DHCP a 192.168.88.x IP and Internet works.

PC connected to Mikrotik via ether2 and ether1 is my WAN. By the way, the LAN which going to ether1 as WAN is coming from a Switch, and when I connect this cable directly to the PC from the Switch I get Static 192.168.88.103 IP address/Gateway: 192.168.88.1. So I can access the internet.

So it is clear that 192.168.88.1 IS the gateway your Mikrotik also has to use via "ether1" (WAN)

...but wait...why don't you simply make "ether1" a "DHCP-client" It seems something "upstream" is providing IP + Gateway information. (because you tested with PC and it worked)

So go to "IP" -> "DHCP Client" and "add" interface "ether1" as DHCP-client.
Then make sure "used peer dns" and "add default route" are selected.
Then see what happens IF you automagically get also a 192.168.88.x IP on that "ether1" port.

Maga · October 7, 2024, 7:23am

I understood earlier in your posts that your “ether1” is your ISP “uplink” AND if you pull out the cable out of your Mikrotik router and put it on a PC it receives via DHCP a 192.168.88.x IP and Internet works.

PC connected to Mikrotik via ether2 and ether1 is my WAN. By the way, the LAN which going to ether1 as WAN is coming from a Switch, and when I connect this cable directly to the PC from the Switch I get Static 192.168.88.103 IP address/Gateway: 192.168.88.1. So I can access the internet.

So it is clear that 192.168.88.1 IS the gateway your Mikrotik also has to use via “ether1” (WAN)

…but wait…why don’t you simply make “ether1” a “DHCP-client” It seems something “upstream” is providing IP + Gateway information. (because you tested with PC and it worked)

So go to “IP” → “DHCP Client” and “add” interface “ether1” as DHCP-client.
Then make sure “used peer dns” and “add default route” are selected.
Then see what happens IF you automagically get also a 192.168.88.x IP on that “ether1” port.

Screenshot from 2024-10-06 20-30-24.png

It is worked. Thank you very much!
I appreciate it.
Thank you for spending your time with me!
Thank you for your attention.
You helped me a lot. Thank you!