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Not Valid Issue


I'm using the verifier tool and I see a few issues I'd like some help resolving.
Question 1: Surely an IP block should be an 'unsure' rather 'invalid' status. or even 'IP Blocked' as status.
Because I normally just remove all invalid emails and many 'valid' ones that just have an IP block on my network are being discarded.'
1) 550 PTR (rDNS) record does not exist for (See RFC1912 2.1) > RSET
Why is this marked as Invalid? Surely it should be unsure because it seems like an IP block?

2) It says 'Not Valid' for
> RCPT TO:<>
< 550
Surely again it's an IP blacklist and should be set as 'unsure' not 'invalid'.

3) and there are many more like this. < 550 5.7.1 <>... Rejected: listed at

Question 2: Proxies
I've tried using some proxies but then it can't verify correctly even if the proxies are passing. What's the best way to do this so I don't keep getting this IP block on many emails.

Help is appreciated.


  • SvenSven
    Q1: I will fix that in next update. You can do that as well when editing the reply filters. However I see that things like this better be managed by myself with updated so please send more of those samples if you find them.

    Q2: Almost all proxies do not allow email verification. Proxy Scraper has a test script added that can test those against email verification. However public know it all ;)

  • AlexRAlexR Cape Town
    Q1) There where a bunch of these. Surely you should have an extra status 'IP Block' instead of unsure or not valid. I can send you some more like this as there where quite a few where there was an IP block marked as invalid.

    Q2) What about private proxies? What do you advise to get the max verify results? Leave proxies completely?
  • SvenSven
    q1: Unsure is basically this Blocking. Please send such entries only when done with new version
    q2: ask the provider if the proxies allow it.
  • AlexRAlexR Cape Town
    Q1) OK. Will do.
    Q2) They don't. Do you know any proxy providers I can use? Is shared or private better option? (I'm not keen to use scraped public proxies)
  • SvenSven
    sorry no
  • AlexRAlexR Cape Town
    If I use a proxy provider that doesn't allow it, what will happen? Will it show up as invalid or unsure?
  • SvenSven
    it most likely does not work at all. they disable port 25.
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