Quick answer. Gmail does not publish a per-IP reputation score, and the IP Reputation dashboard from the legacy Postmaster Tools is not included in v2. To check your standing with Gmail today you combine four sources: Postmaster Tools v2 (spam rate, delivery errors, compliance), the SMTP responses Gmail returns to your servers, Google's sender-guideline requirements for IPs, and an independent daily measurement of each sending IP.
What Gmail does and does not tell you
Gmail evaluates the sending IP on every connection — its sender guidelines and SMTP error reference make that clear — but its internal reputation value is private. The old Postmaster Tools IP Reputation dashboard was the only place Google ever exposed a version of it, as a Bad / Low / Medium / High label per IP and per day, and Google has said that dashboard will be retired rather than carried into v2.
That leaves you with symptoms and independent measurements. Used together they are more than enough to know whether an IP is in trouble and, more importantly, whether it is getting better or worse.
1. Read Postmaster Tools v2 for Gmail-side symptoms
If you send more than a trickle to Gmail, Postmaster Tools v2 is still the first stop. None of its dashboards is per-IP, but three of them react when Gmail's view of your mail deteriorates:
- Spam rate — the share of delivered mail that Gmail users manually mark as spam. Google's sender guidelines set thresholds for bulk senders; sustained high complaint rates are the most common cause of reputation loss.
- Delivery errors — the percentage of authenticated mail that was rejected or temporarily failed, with error categories. A rising temporary-failure rate is often the first Gmail-side sign of an IP being throttled.
- Compliance status — whether you meet the sender guidelines (authentication, spam rate, one-click unsubscribe, DNS requirements). A failing requirement will hurt every IP behind the domain.
Limitation: all of this is domain-wide. If one of eight IPs in a pool is the problem, Postmaster Tools will show the pool's average.
2. Read Gmail's SMTP responses in your logs
Your own mail server logs contain Gmail's opinion of each connection, and Gmail's responses are unusually explicit about the sending IP. These are the ones to grep for, as documented in Google's Gmail SMTP errors and codes reference:
| Response | What Gmail is saying | What to do |
|---|---|---|
| 421 4.7.0 | Temporary rate limiting because of the very low reputation of the sending IP address | Reduce volume from that IP, investigate complaints and list quality, check the IP's history and neighbours |
| 550 5.7.1 | Message rejected as likely suspicious because of the very low reputation of the sending IP address | Stop sending from the IP until the cause is found; review Google's "Why has Gmail blocked my messages?" guidance |
| 421 4.7.28 | An unusual rate of email — or unsolicited email — from your IP address or IP netblock | Check for compromised accounts or scripts, unexpected volume spikes and warm-up pace |
| 550 5.7.28 | An unusual rate of unsolicited email originating from your IP address | Treat as a spam-source signal: audit sources sending through the IP and list acquisition |
| 421 4.7.0 / 451 4.7.23 / 550 5.7.25 | The sending IP has no PTR record, or the PTR's forward DNS does not match the sending IP | Fix reverse and forward DNS so the PTR hostname resolves back to the sending IP |
Two practical notes. First, Gmail returns these per connection, so the log tells you which IP was throttled — the per-IP resolution v2 dashboards lack. Second, by the time you see 550 5.7.1, reputation has usually been falling for a while. That is the argument for the next two methods.
3. Verify the IP against Google's sender guidelines
Google's email sender guidelines contain concrete, checkable requirements for sending IPs. Run through them for every IP, not just the one that is currently failing:
- Reverse DNS. The public IP of a sending SMTP server must have a PTR record that resolves to a hostname, and that hostname must have an A or AAAA record resolving back to the same IP.
- Blocklists. Google explicitly asks senders to make sure a shared IP is not on any internet blocklist. The same discipline applies to dedicated IPs.
- Shared IP awareness. The activity of any sender on a shared IP affects the reputation of all senders on it. If you send through an ESP, know whether your IP is shared and what else runs on it.
- Consistency. Use consistent IPs for a mail stream and avoid sudden large volume changes; reputation is built on predictable behavior.
4. Measure the IP independently every day
The three methods above tell you what Gmail thinks after the fact. An independent monitor tells you how each IP is trending before the rejections arrive. IP Reputation Monitor checks every configured sending IP once a day, scores it 0–100 with the Innova Reputation Score — an independent consolidation of multiple infrastructure and reputation signals — and classifies it Good (80–100), Warning (70–79) or Critical (below 70). Every result is stored, so you can see the day a score started to slide and compare an IP against the rest of its SMTP group.
| IP address | SMTP group | Innova Score | Status |
|---|---|---|---|
| 203.0.113.10 | SMTP-01 | 91 | Good |
| 203.0.113.11 | SMTP-01 | 89 | Good |
| 203.0.113.24 | SMTP-01 | 84 | Good |
| 198.51.100.9 | SMTP-02 | 78 | Warning |
| 198.51.100.14 | SMTP-02 | 75 | Warning |
| 198.51.100.8 | SMTP-02 | 64 | Critical |
| 198.51.100.21 | SMTP-02 | 61 | Critical |
| 192.0.2.25 | SMTP-03 | — | No Data |
It is not Gmail's private score and it does not guarantee inbox placement. What it gives a Gmail-focused team is the missing dimension: which IP, and since when.
A weekly Gmail IP reputation routine
- Daily (2 minutes): open the IP Reputation Monitor report; look at Warning and Critical counts per SMTP group.
- Daily: grep the previous day's logs for
4.7.0,4.7.28,5.7.1and5.7.28responses from Gmail, grouped by sending IP. - Weekly: review Postmaster Tools v2 Spam rate, Delivery errors and Compliance status.
- Weekly: confirm PTR / forward DNS and blocklist status for any IP that moved.
- On any Critical: pull the IP's history, compare it with its group, identify the stream that changed, and act before Gmail escalates from throttling to rejection.