For most users, DNS is just a way to resolve a domain to an IP, but its capabilities go far beyond that. SRV (Service) record is one of the most powerful — it tells the client not only which server to connect to, but also the port and priority. It is used by Microsoft Teams, Skype for Business, SIP telephony, XMPP chat and even Minecraft.
SRV record format
SRV name is written in a special format: _service._protocol.domain. For example, _sip._tcp.sayt.uz or _sipfederationtls._tcp.sayt.uz. The value contains four elements: priority, weight, port and target. This lets the client choose the right server from several options.
Example for Microsoft 365 federation: _sipfederationtls._tcp.sayt.uz IN SRV 100 1 5061 sipfed.online.lync.com. Here 100 is priority (lower is higher), 1 is weight, 5061 is the TLS SIP port, and the target is the server name.
For Microsoft 365 and Teams
If you want to use Microsoft 365 or Teams with your sayt.uz domain, you need several SRV records. The most important are _sip._tls.sayt.uz and _sipfederationtls._tcp.sayt.uz. Without them, federation and external user communication will not work. Microsoft documentation provides exact values — your job is to enter them correctly in the DNS panel.
You will also need CNAME records along with SRV — for example, sip.sayt.uz CNAME sipdir.online.lync.com. Together they let the Teams client locate the right server with zero manual setup on the user side.
For SIP telephony
Why is SRV useful in office IP telephony? Imagine 50 IP phones all knowing sip.sayt.uz. If you change the SIP server, every phone has to be reconfigured manually. With SRV, you change one DNS record and all phones move to the new server automatically.
SRV can also list multiple servers — _sip._udp.sayt.uz with priority 10 and 20. If the first is unreachable, the client falls back to the second. This is a powerful failover mechanism.
XMPP and other services
XMPP (Jabber) also relies on SRV. Records _xmpp-client._tcp.sayt.uz and _xmpp-server._tcp.sayt.uz tell the client where to connect. Useful when building your own chat platform.
Minecraft servers use SRV to let players connect without specifying a port. Normally you would type mc.sayt.uz:25575, but with _minecraft._tcp.mc.sayt.uz the player can just enter mc.sayt.uz.
Sayt.uz practice
22 percent of our customers use Microsoft 365 or their own SIP telephony on their domain. The most common mistake is the SRV name itself — many forget the leading underscores. In 2032 we handled 147 SRV setup tickets with an average completion time of 1 hour 20 minutes. If the domain is registered through us (from 145,000 UZS per year), adding SRV is free. Initial Microsoft 365 federation setup is a separate package at 350,000 UZS and covers 5 SRV plus 4 CNAME records configured automatically.