I'm wanting to change out a router for a customer to a mikrotik so I can have it also run their vpn server. I'm having an issue though when I plug more than one Aastra 6757i phone in they will all show no service. The layout of their network goes from the Mikrotik on ether2 which is handing out DHCP to a switch that has drops going to the offices. Their phones are then plugged into the wall and their pcs are plugged into the pc port on the phones. As long as one phone is plugged in it works fine, but as soon as a second one is plugged in no service will come up and the pcs no longer have internet. I've set up mikrotiks for quite a while, but I am new to setting them up for voip. I'm sure there is some settings that I don't have running, but I have no idea what they would be. Need some help. Thanks.

Hi TheEnsona,
We use the same sort of scenario, MikroTik and Astra, at several locations and we have not had that problem. We are using the exact same model of phone as you are but I was curious what sort of configuration you were using in the phone. Our config is very basic, we use option 66 as often as possible and then the phone downloads a very simple config (the networking portion is not changed from default settings). Also, how are you powering the phones?

Thank you for the reply. The phones are being power by a poe switch that plugs into a normal switch. I'm not quite sure what option 66 is, but this router is set up to do pppoe on ether1, hands out dhcp on ether2. I have a src-nat rule to give the private network internet access and that is basically it. I do have pptp turned on because they will have another business connect in to access files on a server.

Maybe a basic question, but sometimes those get overlooked. Do you have the phones set to use DHCP? If they are set by default to use a particular IP address, they may all be trying to use the same one.

They are set to use dhcp. I've checked the dhcp lease to make sure they were pulling a different one and they are.

Option 66 is a way of providing the the phones the directory to pull their config from via DHCP. So basically, the path to their config file is always present in the DHCP server and the phone itself does not have to be configured by hand other than to tell it what extension it should be. What version of RouterOS are you using? What type of RouterBoard are you using?

Using an RB450G RouterOS v5.26

They are currently using an adtran router, but since we had issues I had to put it back in place. I brought the mikrotik back to the office to set up to our phones and today 2 phones are working fine being plugged up at the same time. I haven't added or changed anything.

That should absolutely work. Have you tried resetting the router and the phones and starting from scratch?

Not too long ago, we were troubleshooting a very strange problem and because the cabling was new and supposedly in good working order we didn't check it right off the bat. Of course, in the end it was the cabling. Have you checked that to see if that is the problem? Try to re-install it, but only one LAN cable at a time and see where the problems originates from.

I'll copy my config and post it incase there is something small I'm missing.

/interface bridge
add l2mtu=1520 name=bridge1
/interface ethernet
set 0 name=ether1-WAN
set 1 name=ether2-LAN
/interface pppoe-client
add add-default-route=yes allow=pap,chap interface=ether1-WAN name=\
pppoe-1 password=******** use-peer-dns=yes user=\
**************
/ip hotspot user profile
set [ find default=yes ] idle-timeout=none keepalive-timeout=2m
/ip pool
add name=dhcp_pool2 ranges=172.16.1.2-172.16.1.254
/ip dhcp-server
add address-pool=dhcp_pool2 disabled=no interface=bridge1 lease-time=1d name=\
dhcp1
/ppp profile
add change-tcp-mss=yes local-address=172.16.1.200 name=pptp use-compression=\
yes use-encryption=yes use-vj-compression=no
/interface bridge port
add bridge=bridge1 interface=ether2-LAN
add bridge=bridge1 interface=ether3
/interface pptp-server server
set authentication=pap,chap,mschap1,mschap2 default-profile=default enabled=\
yes
/ip address
add address=172.16.1.1/24 interface=bridge1
/ip dhcp-client
add default-route-distance=0 disabled=no interface=ether1-WAN
/ip dhcp-server lease
add address=172.16.1.10 mac-address=00:08:5D:2F:69:99 server=dhcp1
add address=172.16.1.9 mac-address=00:08:5D:2F:69:96 server=dhcp1
/ip dhcp-server network
add address=172.16.1.0/24 dns-server=172.16.1.1 gateway=172.16.1.1
/ip dns
set allow-remote-requests=yes servers=**********,**********
/ip dns static
add address=192.168.88.1 name=router
/ip firewall nat
add action=masquerade chain=srcnat out-interface=ether1-WAN src-address=\
172.16.1.0/24
add action=src-nat chain=srcnat disabled=yes src-address=172.16.1.0/24 \
to-addresses=************
/ip firewall service-port
set sip disabled=yes
/ip neighbor discovery
set ether1-WAN disabled=yes
/ip route
add distance=1 dst-address=172.16.1.0/24 gateway=ether2-LAN
/ppp secret
add name=******* password=********** profile=pptp remote-address=172.16.1.201 \
service=pptp
add name=pptp profile=pptp remote-address=172.16.1.202 service=pptp
/system identity
set name="Stainless Innovations"
/system ntp client
set enabled=yes
/tool mac-server
add disabled=no interface=ether2-LAN
add disabled=no interface=ether3
add disabled=no interface=ether4
add disabled=no interface=ether5
/tool mac-server mac-winbox
set [ find default=yes ] disabled=yes
add interface=ether2-LAN
add interface=ether3
add interface=ether4
add interface=ether5

Try removing the static route that is set and turn the SIP helper back on. Other than that I don't see any problems. If you are still having problems after that, then reset the router and re-import the export, don't re-import the back-up file.

Went back through and tested this router with our phones at the office Friday and everything was working fine so we decided to give this another shot. Went out to customer location and changed it over. At first it looked like everything was working and then the problem started up again. I DID however realize what was going on. I don't work for the phone side of the company, but the old router was set up as a /16 network, but was excluding the 0.1-0.254 range and only handing out 1.1-1.254 while using 0.1 as the gateway. When I set the router up, I just set it up as a /24 network because that's pretty much what they were doing anyway but with the gateways being different the equipment running the phones had a static ip assigned pointing to 172.16.0.1 as the gateway instead of 172.16.1.1 which is where the problem was coming from. So for time and ease of changing, I made put the Mikrotik on a 172.16.0.0/16 network, but only handed up 1.1-1.254 in the pool for dhcp and set 172.16.0.1/16 as the gateway. As soon as I did this the problem went away. So far everything has been working fine. Thank you for all your help! I really appreciate it!

No problem. I'm glad to hear that you were able to get it working