A Request for Comments (RFC) is a publication of the Internet Engineering Task Force (IETF) and the Internet Society, the principal technical development and standards-setting bodies for the Internet.

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5
votes
2answers
247 views

What is the difference between 3-digit and dotted SMTP error codes?

When looking up SMTP error codes, I sometimes see "550", or "5.5.0". And sometimes the number in the dotted code is different. I found the numeric codes defined in RFC 821 and the dotted codes in RFC ...
5
votes
2answers
995 views

Formal separation marker of syslog events?

I've been looking at RFC5424 to find the formally specified marker that will end a syslog event. Unfortunately I couldn't find it. So If I wanted to implement some small syslog server that reacts on ...
2
votes
2answers
608 views

IPv6 and Hop Limit

I am reading RFC 2460 about IPv6 and it says that "the packet is discarded if Hop Limit is decremented to zero.", so that is to say that if a router decrements a packet's Hop Limit to 0, other another ...
1
vote
2answers
3k views

Does the OS X DHCP client support classless static routes (RFC3442)?

Simply put: does Mac OS X support RFC3442? RFC3442 implements DHCP codes (121 and 249) to provide classless static routes to DHCP clients. I can only seem to find rather old information circa ...
0
votes
5answers
366 views

Help me understand Public/Private IP space and NAT

I just started working at a small-medium sized business after graduating school. So much of my knowledge is high level concepts without a lot of hands on. My understanding that according to rfc1918 ...
1
vote
1answer
1k views

Space a valid delimiter for email addresses in email header?

Is it syntactically correct to delimit multiple email recipients in the "To" header of an email with spaces only or do I need to use another delimiter (a semicolon or the like)? Example (MIME data ...
0
votes
2answers
222 views

PTR to domain, A record for domain

Does PTR pointing to domain is forbidden? If so - which RFC states that. The same with A record pointing at the domain. As I see, usually, people are trying to avoid such configurations. But I would ...
12
votes
5answers
3k views

Are one-letter host names valid?

RFC-952 (last sentence of point 1 under Assumptions) prohibits single-character host names and I have had experiences (over 7 years ago summer of 2002) where some services would refuse to work with ...
2
votes
3answers
2k views

Can a CNAME be a hostname

This is bit of a theological question, but nonetheless... So, a server has a hostname, let's say the fqdn is hostname.example.com (to be really precise about what I mean, this is the name that is set ...
20
votes
3answers
14k views

DNS using CNAMEs breaks MX records?

We are trying to move all our websites we host to CNAMES as we are planning on moving servers in the new year and would like the ability to move some clients to one server and other clients somewhere ...
0
votes
6answers
4k views

Can I ping 127.0.0.1 if my computer isn't connected to a network?

Does pinging 127.0.0.1 work on your machine if it's not on the network? Can these two machine be on the same network? machine A (192.168.173.11) machine B (192.168.163.11)
35
votes
4answers
42k views

What's the maximum URL length in Tomcat?

And is it configurable? Can I set up Tomcat so that a URL with, say, 200K of query params goes through successfully to the contained servlet? Yes, I know one should use POST when you have lots of ...
11
votes
7answers
4k views

Check public DNS health and RFC compliance

Every now and again I like to run checks on my DNS servers to make sure they are running right and to RFC spec. I used to use the DNSTools website to do this as it gave me a pretty good picture of ...
2
votes
2answers
487 views

Is RFC 1514 still relevant?

Is there any OS-agnostic standard these days better than RFC 1514?
0
votes
3answers
1k views

Is there any difference between prisoner.iana.org, blackhole-1.iana.org, and blackhole-2.iana.org?

Probably not the most useful question, but I'm curious: I understand (in theory) that if a reverse lookup for a private IP makes it makes it past your own DNS servers you should get back ...