I use voip.ms as my voip provider and Zoiper Biz as my softphone. I had Zoiper configured to access the chicago2.voip.ms server and that had been working fine for years. Recently, I configured my router to use the 1.1.1.1 DNS server and forced my computer to get DNS entries from the router. This has not led to any rpoblems, until yesterday…
When I tried placing a call, I got a SIP 503 - DNS timeout error. I reached out to voip.ms and they suggested using the IP address, instead of the domain, and that worked. Strangely, I was able to successfully ping the server from my computer. I posed this question to Zoiper and they responded: This error and the fact that you can connect to the server by IP address indicates that the Cloudflare’s DNS server is not aware of the domain which you are using. There could be many different reasons for that. However I can only suggest that you either use the IP address or return the standard DNS server of your ISP.
I am not sure who to believe at this point. While I can make calls, I would like to understand the cause of the problem in case something like this crops up again. Any ideas/suggestions?
sandro - thank you for taking time to reply, but I am not sure that I understand your question. Within Zoiper->Preferences, where the provider is defined, when I enter chicago2.voip.ms, then I get the DNS timeout error; however, when I enter 208.100.39.53, then the calls are completed.
Note that I was able to successfully ping the server from my computer when I tried ping chicago2.voip.ms (and the reply shows the IP address shown above).
No - I have pointed my computer to my router, i.e., my router is my resolver. Seems odd that I would need to configure the DNS entries in two places (router and computer)…
Many routers out there just have a completely broken DNS forwarder; I have no idea where do they get them, given that there are some very good ones used in the opensource world;
Anyway - I have my own rule for like 20 years now: Never use your router as a DNS server if you don’t want to waste your time randomly.
If you can, have your router set the external DNS servers (like 1.1.1.1 or 8.8.8.8) in its’ DHCP responses. If that is not possible (they must act as a proxy and give their own IP as the DNS server), just hard code the external IPs in your NIC configuration (or resolv.conf if you use a better OS…) for “DNS Servers” and leave just the “Obtain IP” on DHCP.
The part of “resolve fine earlier” and stopped working out of the blue, is exactly the “broken forwarders” I was referring. He already gave an nslookup that shows that going to 1.1.1.1 directly from his PC, resolved chicago2.voip.ms fine ( = no timeout) when it didn’t go through his router’s DNS proxy - which is exactly the symptom I know…
Yeah, it is a better OS. This is why anyone who wants to provide a stable service on the Internet, will use it, and not the other one, which has “some” issues, many of them specifically in the networking domain.
But you requested to do it with nslookup directly to OpenDNS (which already worked without timeout to Cloudflare as well!) - so how will it prove anything? Not that replacing the DNS proxy’s forwarder address to OpenDNS prove anything - those broken resolvers just choke on certain type of DNS responses - which one server might return (at no fault for them), and the other might not. And it depends on the mood of the resolver on top of that. See, that’s why they’re a problem. Also since the 90’s.
This is why anyone who wants to provide a stable service on the Internet, will use it, and not the other one, which has “some” issues, many of them specifically in the networking domain.